JP2022156744A - Analyzer, analysis method, and computer program - Google Patents

Abstract

To easily select a natural vibration mode not dependent on a coordinate system that corresponds to spring-back deformation and easily and reliably carry out analysis for reducing the deformation of a member caused by spring-back.SOLUTION: The present invention finds a physical quantity not dependent on a coordinate system that includes at least one of stress and strain at a plurality of evaluation points of finite element model data, on the basis of finite element model data, material property data and stress distribution data, so as to generate a first distribution vector that indicates the distribution of physical quantity of a member caused by spring-back, finds a physical quantity at the plurality of evaluation points of the finite element model data regarding each natural vibration mode, on the basis of the finite element model data and the material property data, so as to generate a second distribution vector that indicates the distribution of physical quantity of a member in each natural vibration mode, and calculates the inner product of the first distribution vector and a second distribution vector in each natural vibration mode and finds the degree of coincidence.SELECTED DRAWING: Figure 1

Description

The present invention relates to an analysis device, an analysis method, and a computer program.

Due to the demand for collision safety and weight reduction, the tensile strength of steel sheets used for automobile bodies has exceeded the 590 MPa class and is reaching the unit of GPa. A high-strength steel plate can increase energy absorption, strength, etc. at the time of collision without increasing the plate thickness. Compared to other lightweight materials, parts processing and assembly using high-strength steel does not necessarily require major changes in equipment and production technology. Therefore, it is believed that the burden on the production cost of parts processing, assembly, etc. using high-strength steel sheets is relatively small compared to other lightweight materials.

However, in the case of press working, springback, wrinkles, etc. increase as the strength of the steel sheet increases, making it difficult to ensure the dimensional accuracy of the parts. In addition, the decrease in ductility accompanying the increase in strength increases the risk of breakage during press forming. In this way, achieving both performance and productivity with high-strength steel sheets is not necessarily easier than with conventional mild steel sheets. ing.

Of the above-mentioned fractures, wrinkles, and springback, fractures and wrinkles are problems that can occur even when conventional mild steel plates are used, depending on the shape of the part, molding conditions, etc., and there have been many findings and countermeasures. etc. are accumulated. On the other hand, springback is a unique problem when using high-strength steel sheets, and it has not been sufficiently studied yet. It cannot be said that it has achieved practical reliability.

Springback is the work of removing the molded product from the mold after molding, trimming unnecessary parts, and other work to relax the restraint of the parts. It is the elastic deformation that occurs in the part. Since the high-strength steel sheet has a large springback, it becomes difficult to secure the dimensional accuracy required for the final product.

Springback is classified into "angle change", "wall warp", "twist", "ridge line warp", and "punch bottom springback" according to the phenomenon. In either case, the residual stress distribution within the part acts as a bending or torsional moment, resulting in deformation of the part depending on the rigidity determined by the elastic modulus of the material, the plate thickness, the shape of the part, and the like. For example, the best known examples of springback are bend angle changes, wall warpage, and the like. These springbacks are driven by the stress distribution in the plate thickness direction, and the rigidity is mainly determined by the plate thickness. Alternatively, draw forming a beam with a longitudinally curved hat cross-section can cause wall warpage and twisting, but a small curvature of curvature increases part stiffness and reduces wall warpage.

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

Increased resistance to springback certainly reduces dimensional change. The resistance to springback is the stiffness of a part to its elastic deformation modes. The shape of the part is an important factor in increasing the rigidity of the part. Since the shape of parts is restricted by requirements such as performance and layout, small measures such as beads and embossments are effective.

Beads against wall warpage are the most typical examples of stiffening measures. On the other hand, it is not easy to find the optimum rigid reinforcement position for three-dimensional springback in complicated parts. As a new attempt, a method has been proposed in which natural vibration analysis and optimization are used together (see Non-Patent Document 1).

That is, focusing on the fact that the eigenfrequency is proportional to the square root of stiffness and inversely proportional to the square root of density (mass), the elastic deformation mode of springback is specified, and the eigenfrequency corresponding to the elastic deformation mode of springback is determined. Select a vibration mode, replace part of the elements with highly elastic material of the same density so that the natural frequency of the natural vibration mode increases, and find the optimum arrangement of the elements using an optimization tool, etc. . This makes it easy to find the optimum stiffening position.

However, this method has the problem that the natural vibration mode must be selected manually, which is time-consuming. Also, even if the natural vibration mode is automatically selected, it is not always possible to select the natural vibration mode corresponding to the elastic deformation mode of springback because the selection criteria are not clear. It wasn't. Therefore, it is conceivable to select all the natural vibration modes and obtain the optimum arrangement of the highly elastic material for each, but there is a problem that the cost is too high. For this reason, it has not been possible to easily perform an analysis for reducing the deformation of members caused by springback.

Therefore, when selecting which natural vibration mode the shape after springback corresponds to, a method of comparing the springback displacement and the eigenvector of each natural vibration mode can be considered. In this case, the orientation (coordinate system) of the member before springback must match the orientation of the member in the natural vibration mode analysis. Also, if the attitude after springback changes greatly depending on the restraint position of springback, it may not be possible to select the correct mode even if the attitude before springback is matched.

Shunji Hiwatari, 1 person, "Comprehensive Approach to Forming Problems of High-strength Steel Plates", Special Lecture Meeting of Plate Forming Forum, Creative Engineering Division, Iron and Steel Institute of Japan, The Iron and Steel Institute of Japan, January 14, 2005

The present invention has been made to solve such conventional problems. For vectors generated by arranging physical quantities that do not depend on the posture (coordinate system) of a member, the inner product after springback and each natural vibration mode is calculated. The purpose is to easily select the natural vibration mode that does not depend on the coordinate system by calculating and evaluating the degree of matching, and to easily and reliably perform analysis to reduce the deformation of members caused by springback. and

The analysis apparatus of the present invention comprises a press forming analysis unit that acquires finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member; Based on the finite element model data, the material physical property data, and the stress distribution data, a coordinate system independent physical quantity including at least one of stress and strain is obtained at a plurality of evaluation points of the finite element model data. a springback analysis unit that generates a first distribution vector indicating the distribution of the physical quantity of the member caused by springback; a natural vibration analysis unit that generates a second distribution vector indicating the distribution of the physical quantity of the member in each of the natural vibration modes by obtaining the physical quantity at a plurality of evaluation points of the finite element model data; a mode decomposition unit that calculates an inner product between a vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of coincidence; and selects one or more natural vibration modes based on the degree of coincidence. and a mode selection unit.

In the analysis device of the present invention, the physical quantity is at least one of stress, strain, and strain energy density.

2. The analysis apparatus according to claim ₁ , wherein the physical quantity is at least _one of the following invariants J1, J2, _{J3 ,} I1, _I2 , and _I3 : analysis equipment. σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

The analysis method of the present invention includes a press forming analysis step of obtaining finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member; Based on the finite element model data, the material physical property data, and the stress distribution data, a coordinate system independent physical quantity including at least one of stress and strain is obtained at a plurality of evaluation points of the finite element model data. a springback analysis step of generating a first distribution vector indicating the distribution of the physical quantity of the member caused by springback; a natural vibration analysis step of generating a second distribution vector indicating the distribution of the physical quantity of the member in each of the natural vibration modes by obtaining the physical quantity at a plurality of evaluation points of the finite element model data; A mode decomposition step of calculating the inner product of the vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of matching, and selecting one or more natural vibration modes based on the degree of matching. At least a mode selection step is performed.

In the analysis method of the present invention, the physical quantity is at least one of stress, strain, and strain energy density.

2. The analysis method according to claim ₁ , wherein the physical quantity is at least _one of the following invariants J1, J2, _{J3 ,} I1, _I2 , and _I3 : analysis equipment. σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

The computer program of the present invention comprises a press forming analysis step of acquiring finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member; Based on the finite element model data, the material physical property data, and the stress distribution data, a coordinate system independent physical quantity including at least one of stress and strain is obtained at a plurality of evaluation points of the finite element model data. a springback analysis step of generating a first distribution vector indicating the distribution of the physical quantity of the member caused by springback; a natural vibration analysis step of generating a second distribution vector indicating the distribution of the physical quantity of the member in each of the natural vibration modes by obtaining the physical quantity at a plurality of evaluation points of the finite element model data; A mode decomposition step of calculating the inner product of the vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of coincidence, and selecting one or more natural vibration modes based on the degree of coincidence. and causing a computer to perform a mode selection step.

In the computer program of the present invention, the physical quantity is at least one of stress, strain, and strain energy density.

In the computer program of the present invention, the physical quantity is at _{least one} of the following invariants J1, J2, _{J3 ,} I1, _I2 , _I3 . σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

According to the present invention, it is possible to easily select a natural vibration mode that does not depend on a coordinate system and that corresponds to springback deformation. Therefore, it is possible to easily and reliably perform analysis for reducing deformation of members caused by springback.

It is a flow chart explaining an example of operation of an analysis device by this embodiment. FIG. 4 is a schematic diagram showing an example of members before and after being divided into elements; It is a block diagram showing an example of functional composition of an analysis device by this embodiment. FIG. 5 is a characteristic diagram showing the degree of matching between stress distribution data in springback analysis results and stress distribution data for each natural vibration mode in natural vibration analysis results. 2 is a schematic diagram showing the internal configuration of a personal user terminal device; FIG.

Various embodiments of the present invention will now be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to those embodiments, but extends to the invention described in the claims and equivalents thereof.

FIG. 1 is a flow chart for explaining an example of the operation of the analysis device 1. As shown in FIG. The processing flow shown in FIG. 1 is based on a program pre-stored in the storage unit 12 of the analysis device 1 shown in FIG. work and be executed. Note that the configuration of the analysis device 1 will be described later.

First, the processing unit 13 divides the shape of the member into a plurality of elements of specific shape and size based on the “CAD model data and generation condition data” stored in the storage unit 12, thereby obtaining a finite Element model data is generated (step S101). The processing unit 13 also stores the generated finite element model data in the storage unit 12 . HyperMesh, which is a commercially available application program, is used for the finite element model generation process. However, it is also possible to use other application programs (ANSA, etc.).

FIG. 2(a) is a schematic diagram (perspective view) showing the orientation of the target member incorporated into the structure. FIG. 2B is a schematic diagram (perspective view) showing a posture at the completion of molding in the molding analysis of the target member.

Next, the processing unit 13 obtains the stress generated in each element of the member by the finite element method based on the finite element model data, the material physical property data, and the press molding condition data stored in the storage unit 12. , to generate stress distribution data of the member (step S102). In this way, the stress distribution data of the member includes information indicating the stress generated in each element of the member. The processing unit 13 also stores the generated stress distribution data in the storage unit 12 . HyperForm, which is a commercially available application program, is used for analysis processing of press molding. However, it is also possible to use other application programs (LS-DYNA, PAM-STAMP, ABAQUS, etc.).

Next, based on the finite element model data, the stress distribution data, the material physical property data, and the boundary condition data stored in the storage unit 12, the processing unit 13 determines the member at a plurality of evaluation points of the finite element model data. Physical quantities independent of orientation (coordinate system) are obtained by the finite element method and arranged in order of evaluation points to generate a first distribution vector indicating the distribution of the physical quantities of the member caused by springback (step S103). As the physical quantity, stress (maximum principal stress, minimum principal stress), strain (maximum principal strain, minimum principal strain), strain energy density, various invariants, and the like can be used. An evaluation point may be an arbitrary point such as an integration point or a node (or all nodes) within an arbitrary element (or all elements) in the finite element model data.

The first distribution vector when the physical quantity is the maximum principal strain is shown in the following equation (8). (8), ε _1,SB represents the maximum principal strain after springback, n is the number of evaluation points, and N is the number of candidate modes.
Also, the first distribution vector when the physical quantity is the maximum principal strain and the minimum principal strain is shown in the following equation (9). In equation (9), ε ₁ to _2,SB represent the maximum principal strain and minimum principal strain after springback, n is the number of evaluation points, and N is the number of candidate modes.
In addition, the following equations (1) to (7) are given when the physical quantities are strain energy density U and various invariants J ₁ , J ₂ , J ₃ , I ₁ , I ₂ , and I ₃ . In these equations, σ is stress, ε is strain, δ is Kronecker's delta, and det is determinant.

The processing unit 13 stores the generated first distribution vector in the storage unit 12 . Note that LS-DYNA, which is a commercially available application program, is used for springback analysis processing. However, it is also possible to use other application programs (PAM-STAMP, etc.).

Next, the processing unit 13 generates a finite The physical quantities at a plurality of evaluation points of the element model data are obtained by the finite element method and arranged in the order of the evaluation points. Thereby, a second distribution vector indicating the distribution of the physical quantity of the member in each natural vibration mode is generated (step S104).

The second distribution vector in each natural vibration mode when the physical quantity is the maximum principal strain is shown in the following equation (10). (10), ε _1,M represents the maximum principal strain in each natural vibration mode, n is the number of evaluation points, and N is the number of candidate modes.
Also, the second distribution vector in each natural vibration mode when the physical quantity is the maximum principal strain and the minimum principal strain is shown in the following equation (11). In equation (11), ε _1,M represents the maximum principal strain in each natural vibration mode, ε _2,M represents the minimum principal strain in each natural vibration mode, n is the number of evaluation points, and N is a candidate. is the number of modes.

The processing unit 13 stores each generated second distribution vector in the storage unit 12 . OptiStruct, which is a commercially available application program, is used for analysis processing of the natural vibration. However, it is also possible to use other application programs (such as Nastran).

Next, the processing unit 13 calculates the inner product of the first distribution vector stored in the storage unit 12 and the second distribution vector in each natural vibration mode, and obtains the degree of matching between the distribution vectors ( step S105). That is, at each evaluation point, the processing unit 13 calculates the degree of relevance between the physical quantity in each natural vibration mode and the physical quantity after springback by calculating the absolute value of the inner product as the magnitude of each distribution vector. The degree of matching between the distribution vectors is obtained by obtaining the value normalized by , as an index.

Specifically, when the physical quantity is, for example, the maximum principal strain, the processing unit 13 obtains the matching degree d between the distribution vectors as a vector from the following equation (12). The element d _i of the vector d indicates the degree of coincidence between the ith natural vibration mode and the maximum principal strain after springback. A larger value of d _i indicates a higher degree of matching between the distribution vectors. The processing unit 13 stores each obtained degree of matching between the distribution vectors in the storage unit 12 .

Assuming that the physical quantities are the maximum principal strain and the minimum principal strain, the processing unit 13 obtains the matching degree d between the distribution vectors as a vector using the following equation (13). The element d _i of the vector d indicates the degree of matching between the i-th order natural vibration mode and the maximum principal strain and minimum principal strain after springback. A larger value of d _i indicates a higher degree of matching between the distribution vectors. The processing unit 13 stores each obtained degree of matching between the distribution vectors in the storage unit 12 .

Next, the processing unit 13 selects one or more (a small number), here two natural vibration modes, based on each degree of matching between the distribution vectors stored in the storage unit 12 (step S106). . Unlike this embodiment, when the degree of matching between distribution vectors is evaluated using the shape (displacement) of a member, the relationship between the order of the natural vibration mode and the degree of matching between distribution data must be the same for the model posture. Otherwise, a correct degree of matching cannot be obtained, and the natural vibration mode corresponding to the deformation of the member caused by springback cannot be selected. On the other hand, in this embodiment, the degree of coincidence between distribution vectors is determined by physical quantities (stress (maximum principal stress, minimum principal stress), strain (maximum principal strain, minimum principal , strain energy density, various invariants, etc.). Accordingly, as will be described later in this embodiment, the processing unit 13 selects, for example, the primary mode and the sixth mode as the natural vibration modes corresponding to the deformation of the member caused by springback, based on the degree of matching between the distribution vectors. can be selected.

Next, the processing unit 13 stores the generated natural vibration mode based on the material physical property data, the boundary condition data, and the arrangement condition data stored in the storage unit 12 so that the natural frequency increases. A bead is placed on the finite element model data stored in the unit 12 (step S107).

Here, placing a bead in the finite element model data means making the surface of a member belonging to the element included in the finite element model data uneven. As described above, the bead in the present invention means that the surface of the member is made uneven, and is a concept including embossing and the like.

Then, the processing unit 13 stores the finite element model data after the beads are arranged in the storage unit 12 . OptiStruct, which is a commercially available application program, is used for bead placement processing. In addition, when arranging the bead, the ratio of the bead arrangement area to the member area can be specified. Here, the member area is the area of the surface on which the bead can be arranged among the surfaces of the member. The bead arrangement area is the area of the portion of the surface of the member where the bead is arranged. If this ratio is too large, the bead will be placed over a large area of the member. However, depending on the shape of the member, the location where the member is attached, the relationship with other members, and the like, restrictions may be imposed on the area where the bead is arranged. In addition, there are cases where it is desired to make the design of the member easier by setting the bead arrangement only in the region that greatly contributes to suppressing the deformation of the member caused by springback. From this point of view, the user appropriately designates the ratio of the bead arrangement area to the member area by operating the operation unit 14 .

Next, the processing unit 13 causes each element of the member to generate The stress distribution data of the member is updated by obtaining the stress applied by the finite element method (step S108). In addition, the processing unit 13 stores the generated “stress distribution data after the bead is arranged” in the storage unit 12 . HyperForm, which is a commercially available application program, is used for analysis processing of press molding. However, it is also possible to use other application programs (LS-DYNA, PAM-STAMP, etc.).

Next, the processing unit 13 adds the “after-update "stress distribution data" is mapped (step S109). Then, the processing unit 13 calculates the finite element model data based on the finite element model data to which the stress distribution data after the update is mapped and the "material property data and boundary condition data" stored in the storage unit 12. The physical quantities at a plurality of evaluation points are determined by the finite element method and arranged in the order of the evaluation points to generate a first distribution vector indicating the distribution of the physical quantities of the member caused by springback (step S109). In addition, the processing unit 13 stores the “first distribution vector after bead placement” generated in this manner in the storage unit 12 . Note that LS-DYNA, which is a commercially available application program, is used for springback analysis processing. However, it is also possible to use other application programs (PAM-STAMP, etc.).

Next, the processing unit 13 determines whether the difference between the physical quantity of each node of the member determined based on the first distribution data after the bead is placed and the target physical quantity of the member is within a predetermined range. It is determined whether or not (step S110). This determination can be realized, for example, by determining whether all the differences between the physical quantity at each node of the member on which the bead is arranged and the target physical quantity at each node are within a predetermined range. .

As a result of this determination, if the difference between the physical quantity of the member determined based on the first distribution vector after bead placement and the target physical quantity of the member is not within a predetermined range, the process returns to step S104. . Then, the difference between the physical quantity of the member determined based on the first distribution vector after the bead is arranged and the target physical quantity of the member is stored in the storage unit 12 until the difference falls within a predetermined range. The processing of steps S104 to S110 is repeated using the “(latest) finite element model data after the bead has been placed”. Then, when the difference between the physical quantity of the member determined based on the first distribution vector after the bead is arranged and the target physical quantity of the member falls within a predetermined range, the processing unit 13 performs The display unit 15 is caused to display information specifying a bead arrangement (the latest bead arrangement obtained in step S107) in which the difference between the physical quantity of the member and the target physical quantity is within a predetermined range. Then, the processing according to the flowchart of FIG. 1 ends. The information specifying the bead arrangement may include, for example, information such as the position, shape, height (depth) of the bead, in addition to the image. Further, the display unit 15 displays information indicating the natural vibration mode (latest natural vibration mode obtained in step S106) selected when the physical quantity of the member after springback and the physical quantity of the target are within a predetermined range. can be displayed in

In the process of step S111, for example, information specifying bead arrangement is displayed. However, the bead shape is complicated. Therefore, it is not easy to arrange the beads on the member according to the information. Therefore, the user determines the actual bead placement (that is, the shape of the member) on the member based on the bead placement in the information, the shape and mounting position of the member, the relationship with other members, and the like.

In this manner, the processing unit 13 of the analysis device 1 performs press forming analysis, springback analysis, natural vibration analysis, etc. on the finite element model data. In addition, the processing unit 13 selects one or more natural vibration modes based on the degree of matching of the physical quantities, and arranges beads in the finite element model data so that the natural vibration frequency of this natural vibration mode increases. . Then, the processing unit 13 performs press forming analysis and springback analysis again on the finite element model data after the beads have been arranged. Then, bead placement, press forming analysis, and springback analysis are repeated until the difference between the physical quantity of the member after the springback analysis and the target physical quantity falls within a predetermined range. This allows the user to easily select the natural vibration mode corresponding to the springback deformation.

In addition, in the flowchart of FIG. 1, the processing of steps S108 and S110 may be omitted. In this case, in step S109, "each finite element model data after bead placement" stored in the storage unit 12 is replaced with the "member model data" generated in step S102 and stored in the storage unit 12. map the stress distribution data of

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

Under the above conditions, press forming analysis, springback analysis, natural vibration analysis, and mode decomposition were performed. The agreement relationship between the stress distribution data was obtained. For comparison, FIG. 4 also shows the degree of matching obtained from the conventional technique, that is, the displacement vector, which is the coordinate difference between the stress distribution data and the target shape, and the eigenvector of the natural vibration mode obtained by the natural vibration analysis. It also shows the degree of agreement between

In this embodiment, the degree of coincidence between distribution vectors is determined by physical quantities (stress (maximum principal stress, minimum principal stress), strain (maximum principal strain, minimum principal strain), strain energy density , various invariants, etc.). For example, as a plurality of integration points, evaluation is performed at two points, namely, the central portion of the plate thickness and the surface layer portion of the upper surface of the plate thickness, and two types of characteristic diagrams obtained corresponding to each integration point are created. The stress at the center of the plate thickness causes torsional deformation, and the stress at the surface layer of the upper surface of the plate causes bending deformation. From the two types of characteristic diagrams, only the 1st-order mode and the 6th-order mode have a high degree of agreement for both integration points. On the other hand, the degree of coincidence between the displacement vector, which is the coordinate difference between the springback analysis result and the target shape, and the eigenvector of the natural vibration mode obtained by the eigenfrequency analysis (the degree of coincidence obtained from the conventional technology) is the model of the eigenvalue analysis. Since there is a difference in the posture of the model for the and forming analysis, it becomes almost zero in all modes, and the eigenmode cannot be extracted from the deformation due to springback.

Finally, the hardware configuration of the analysis device 1 in this embodiment will be described. FIG. 3 is a block diagram showing an example of the functional configuration of the analysis device 1. As shown in FIG.

The analysis device 1 executes programs already installed, refers to data stored in the storage unit 12 and/or data stored in other devices, and executes various processes. In addition, the analysis device 1 executes various processes according to instructions input by the user via the operation unit 14 and presents the results to the user via the display unit 15 . Therefore, 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 .

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 via a network from another device (not shown) to the processing unit 13 . Also, the communication unit 11 transmits the data received from the processing unit 13 to another device via the network.

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, and the like used for processing in the processing unit 13 . The storage unit 12 stores, for example, application programs such as a finite element model generation program, a press forming analysis program, a springback analysis program, a natural vibration analysis program, a mode decomposition program, a mode selection program, and a bead arrangement program.

The storage unit 12 also stores the following data and the like as preset initial setting data.
As first initial setting data, the storage unit 12 stores CAD (Computer Aided Design) model data indicating the position, size, and shape of members. As the second initial setting data, the storage unit 12 stores material property data indicating the material property of the member (dimension, 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 conditions for generating the finite element model (element shape, size, etc.). As the fourth initial setting data, the storage unit 12 stores press forming condition data indicating press forming 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 members, etc.). As the sixth initial setting data, the storage unit 12 stores placement condition data indicating bead placement conditions (height, placement area, etc.).

The storage unit 12 also stores the following data and the like 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 (the position, shape, size, etc. of each element) corresponding to the CAD model data. As the second intermediate data, the storage unit 12 stores stress distribution data indicating the stress distribution of the member. As the third intermediate data, the storage unit 12 stores the first distribution vector indicating the distribution of the physical quantity of the member caused by springback. As fourth intermediate data, the storage unit 12 stores second distribution data indicating the distribution of the physical quantity of the member in each natural vibration mode. As fifth intermediate data, the storage unit 12 stores the degree of matching between distribution vectors. As the sixth intermediate data, the storage unit 12 stores the selected order of the natural vibration mode. As the seventh intermediate data, the storage unit 12 stores the finite element model data after the bead has been arranged. As the eighth intermediate data, the storage unit 12 stores distribution data indicating the distribution of the physical quantity after the bead is arranged.
Furthermore, the storage unit 12 may temporarily store temporary data related to predetermined processing.

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 controls the overall operation of the analysis device 1 . That is, the processing unit 13 controls the communication unit 11, the display unit, and the like so that various processes of the analysis device 1 are executed in appropriate procedures based on the operation of the operation unit 14, the programs stored in the storage unit 12, and the like. 15 and so on. The processing unit 13 executes processing based on programs (operating system program, application program, etc.) stored in the storage unit 12 . Also, the processing unit 13 can execute a plurality of programs (application programs, etc.) in parallel.

The processing unit 13 includes a finite element model generating unit 131 that executes the processing of step S101 in FIG. An analysis unit 133, a natural vibration analysis unit 134 that executes the process of step S104, a mode decomposition unit 135 that executes the process of step S105, a mode selection unit 136 that executes the process of step S106, and a process of step S107. It has a bead placement unit 137 that executes, an invariant determination unit 138 that executes the process of step S110, and a data drawing unit 139 that executes the process of step S111. Each of these units included in the processing unit 13 is a functional module implemented by a program executed on the processor included in the processing unit 13 . Alternatively, these units included in the processing unit 13 may be implemented in the analysis device 1 as firmware.

The data drawing unit 139 executes data drawing processing. That is, the data given from the finite element model generation unit 131, the press forming analysis unit 132, the springback analysis unit 133, the natural vibration analysis unit 134, the mode decomposition unit 135, the mode selection unit 136, and the bead placement unit 137 are analyzed. , the data is rendered in a predetermined format (for example, a contour map) to generate drawing data. The data drawing unit 139 then outputs the generated drawing data to the display unit 15 or the like. In this case, the display section 15 functions as an output section. However, this need not necessarily be the case. For example, the communication unit 11 is given from a finite element model generation unit 131, a press forming analysis unit 132, a springback analysis unit 133, a natural vibration analysis unit 134, a mode decomposition unit 135, a mode selection unit 136, and a bead placement unit 137. When transmitting the received data to an external device, the communication section 11 functions as an output section.

The operation unit 14 may be any device as long as it can operate the analysis device 1 , such as a keyboard and a touch panel. The user can use this device to input instructions such as selection. The operation unit 14 generates a signal corresponding to the operation when operated by the user. The generated signal is input to the processing unit 13 as a user's instruction.

The display unit 15 may be any device as long as it can display video, images, etc., for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, or the like. The display unit 15 displays video, images, and the like according to the drawing data supplied from the processing unit 13 .

As described above, in the present embodiment, physical quantities (stress (maximum principal stress, minimum principal stress), strain (maximum principal strain, minimum principal strain), (strain energy density, various invariants, etc.) can be easily selected, and analysis for reducing member deformation caused by springback can be easily performed.

In this embodiment, the physical quantity of the member in the springback analysis is stress (maximum principal stress, minimum principal stress), strain (maximum principal strain, minimum principal strain), strain energy density, various invariants, and the like. Although the case of using one of them has been exemplified, any two or all three of these may be used. By using a plurality of physical quantities, the natural vibration modes corresponding to these physical quantities can be selected more accurately, and the deformation of the member caused by springback can be reliably reduced. Also, the shape of the member (the natural vibration deformation mode corresponding to the shape after springback is selected) may be added to these physical quantities.

In addition, the present invention is not limited to this embodiment. For example, in the present embodiment, the analysis device 1 has the units shown in FIG. 3, but some of them may be included in a server device (not shown). The server device has, for example, a storage unit corresponding to the storage unit 12 of the analysis device 1, provides programs, data, etc. stored in the storage unit to the analysis device 1, and causes the analysis device 1 to perform analysis processing. You may do so. In this case, the processing unit 13 of the analysis device 1 acquires programs, data, etc. from the server device via the communication unit 11 . On the other hand, when storing programs, data, etc. in the storage unit 12 of the analysis device 1 , the processing unit 13 acquires the programs, data, etc. from the storage unit 12 .

Further, the server device has a storage unit and a processing unit corresponding to the storage unit 12 and the processing unit 13 of the analysis device 1, and executes analysis processing using programs, data, etc. stored in the storage unit. Only the result may be provided to the analysis device 1 .

That is, the present embodiment described above can be realized by a computer executing a program. The function of each component of the analysis apparatus according to this embodiment (each part 131 to 139 of the processing part 13 in FIG. 3, etc.) is realized by running a program stored in a computer's RAM (Random Access Memory), ROM, etc. can. Similarly, each step of the analysis method according to this embodiment (steps S101 to S111, etc. in FIG. 1) can be implemented by running a program stored in the RAM, ROM, or the like of a computer. A program for realizing the function of each component of the analysis apparatus according to this embodiment (each part 131 to 139 of the processing unit 13 in FIG. 3, etc.), each step of the analysis method according to this embodiment (step S101 to FIG. 1) S111, etc.) may be loaded into the memory and executed to realize the function.

The storage unit 12 of the analysis apparatus 1 shown in FIG. 3 includes 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, and a volatile memory such as a RAM. It may be configured by a memory of the same type, or a combination thereof.

In addition, a program for realizing various functions of each component of the analysis apparatus according to this embodiment (each unit 131 to 139 of the processing unit 13 in FIG. 3, etc.) is recorded on a computer-readable recording medium, and this recording medium You may perform the process of each component by making a computer system read and execute the program recorded on . It should be noted that the "computer system" referred to here includes hardware such as an OS and peripheral devices.

The "computer system" may also include the home page providing environment (or display environment) if the WWW system is used.
The term "computer-readable recording medium" refers to portable media such as flexible discs, magneto-optical discs, ROMs and CD-ROMs, and storage devices such as hard discs incorporated in computer systems. In addition, "computer-readable recording medium" means dynamically storing a program for a short period of time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. However, it may also include something that retains the program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or client in that case. Further, the above program may be for realizing part of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in the computer system. .

As a specific example, the analysis apparatus shown in this embodiment has a computer function 100 as shown in FIG.
The computer function 100 includes a CPU 101, a ROM 102, and a RAM 103, as shown in FIG. It also has a controller (CONSC) 105 for an operation unit (CONS) 109 and a display controller (DISPC) 106 for a display (DISP) 110 as a display unit such as a CRT or LCD. Further, 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 are provided. 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.

The CPU 101 executes software stored in the ROM 102 or HD 111 , or software supplied from the STD 112 to collectively control each component connected to the system bus 104 . That is, the CPU 101 reads and executes a processing program (analysis program) for performing the above-described operations from the ROM 102, HD 111, or STD 112, thereby performing control for realizing the operations in this embodiment. The RAM 103 functions as a main memory, work area, or the like for the CPU 101 .

CONSC 105 controls instruction input from CONS 109 . DISPC 105 controls the display of DISP 110 . The DCONT 107 controls access to the HD 111 and STD 112 that store boot programs, various applications, user files, network management programs, and the processing programs described above in this embodiment. NIC 108 exchanges data bi-directionally with other devices on network 113 .
Note that, instead of using the personal user terminal device, a predetermined computer or the like specialized for the analysis device of this embodiment may be used.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, for molding members applied to automobile bodies and the like.

11 communication unit 12 storage unit 13 processing unit 14 operation unit 15 display unit

Claims (9)

a press forming analysis unit that acquires finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member;
Based on the finite element model data, the material physical property data, and the stress distribution data, coordinate system-independent physical quantities including at least one of stress and strain at a plurality of evaluation points of the finite element model data a springback analysis unit that generates a first distribution vector indicating the distribution of the physical quantity of the member caused by springback;
Based on the finite element model data and the material physical property data, the physical quantity of the member in each natural vibration mode is obtained by obtaining the physical quantity at a plurality of evaluation points of the finite element model data for each natural vibration mode. a natural vibration analysis unit that generates a second distribution vector indicating the distribution of
a mode decomposition unit that calculates an inner product of the first distribution vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of coincidence;
a mode selection unit that selects one or more natural vibration modes based on the matching degree;
An analysis device comprising: 2. The analysis apparatus according to claim 1, wherein the physical quantity is at least one of stress, strain, and strain energy density. _2. The analysis apparatus according to claim ₁ , wherein said physical quantity is at _{least one} of the following invariants J1, J2, J3, I1, _I2 , _I3 . σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

a press forming analysis step of acquiring finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member;
Based on the finite element model data, the material physical property data, and the stress distribution data, coordinate system-independent physical quantities including at least one of stress and strain at a plurality of evaluation points of the finite element model data a springback analysis step of generating a first distribution vector indicating the distribution of the physical quantity of the member caused by springback;
Based on the finite element model data and the material physical property data, the physical quantity of the member in each natural vibration mode is obtained by obtaining the physical quantity at a plurality of evaluation points of the finite element model data for each natural vibration mode. a natural vibration analysis step of generating a second distribution vector indicating the distribution of
a mode decomposition step of calculating the inner product of the first distribution vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of coincidence;
a mode selection step of selecting one or more natural vibration modes based on the matching degree;
An analysis method characterized by performing at least 5. The analysis method according to claim 4, wherein the physical quantity is at least one of stress, strain, and strain energy density. 5. The analysis method according to claim ₄ , wherein the physical quantity is at _{least one} of the following invariants J1, J2, _J3 , I1, _I2 , _I3 . σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

a press forming analysis step of acquiring finite element model data indicating the shape of a member, material property data indicating material properties of the member, and stress distribution data indicating the stress distribution occurring in the member;
Based on the finite element model data, the material physical property data, and the stress distribution data, coordinate system-independent physical quantities including at least one of stress and strain at a plurality of evaluation points of the finite element model data a springback analysis step of generating a first distribution vector indicating the distribution of the physical quantity of the member caused by springback;
Based on the finite element model data and the material physical property data, the physical quantity of the member in each natural vibration mode is obtained by obtaining the physical quantity at a plurality of evaluation points of the finite element model data for each natural vibration mode. a natural vibration analysis step of generating a second distribution vector indicating the distribution of
a mode decomposition step of calculating the inner product of the first distribution vector and each of the second distribution vectors in each of the natural vibration modes to obtain a degree of coincidence;
a mode selection step of selecting one or more natural vibration modes based on the degree of matching;
A computer program characterized by causing a computer to execute 8. A computer program as recited in claim 7, wherein the physical quantity is at least one of stress, strain, and strain energy density. 8. A computer program according to claim ₇ , wherein said physical quantity is at _{least one} of the following invariants J1, J2, _J3 , I1, _I2 , _I3 . σ is the stress, ε is the strain, δ is the Kronecker delta, and det is the determinant.

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