JP6501959B1 - Simulation system for springback suppression design by shape change, simulation method for springback suppression design by shape change, and program of simulation system for springback suppression design by shape change - Google Patents

Abstract

An object of the present invention is to reduce the operation time and the calculation cost significantly, since it is possible to simultaneously consider the location of the shape change and the influence of the shape change without trial and error or reworking.
SOLUTION: A press forming simulation unit 110, a spring back analysis unit 120, a setting unit 130 for setting a position to be subjected to shape change processing and a shape in shape change according to an input, and a processing to perform shape change processing A model creation unit 140 that creates a model of an affected area having a predetermined distance from the outer edge of the area and the processing area, a processing area stress calculation unit 145 that calculates stress in the processing area, stress data of press molding simulation results, and processing The springback analysis unit 120 includes a synthesis unit 150 that synthesizes the stress data of the area stress calculation result and an influence area stress calculation unit 160 that calculates the stress of the influence area. Springback analysis is newly performed based on the data and the stress data of the stress calculation result of the affected area.
[Selected figure] Figure 16

Description

  The present invention relates to a simulation system for springback suppression design by shape change, a simulation method for springback suppression design by shape change, and a program of the simulation system.

  In the design and development of press molding dies for automobile parts and the like, simulation is used to predict defects during molding in advance. One of the problems at the time of molding is the problem of dimensional accuracy (imprecision) caused by springback deformation. In recent years, springback deformation is large and accuracy inaccuracy is increasing due to the frequent use of high-tensile material or super-high-tensile material.

  As a countermeasure, as in Patent Document 1, a shape change such as a shape freezing bead or embossing is performed on a specific place. In this case, there are two types of shape change: a type in which the shape is added at the final molding (shape addition) and a type in which the shape added immediately before the final molding is not present (shape addition and subtraction) Where to add and types are used in combination.

JP 2007-229724 A

  However, according to the method of Patent Document 1, simulation is used to identify the location to which the shape change is applied, but the effect of the location identification and the shape change is determined independently, so it is simultaneously determined at a plurality of locations. In the case of making a shape change, trial and error are required.

  Making the shape change and performing the exact simulation again increases the operation time and the calculation cost. Moreover, in the re-analysis method using a mesh, the working time to make it into CAD data is required after measures are decided.

  Therefore, the present invention can consider the location of the shape change and the influence of the shape change simultaneously, and can reduce spring time and calculation cost without causing trial and error or rework, and can reduce springback by design change. It is an object of the present invention to provide a simulation system for the above, a simulation method for springback suppression design by shape change, and a program of the simulation system.

  In order to solve the above problems, a simulation system for springback suppression design by shape change according to the present invention, a simulation method for springback suppression design by shape change, and a program of the simulation system are configured as follows. It is characterized by having done.

One aspect of a simulation system for springback suppression design by shape change according to the present invention is
A press forming simulation unit for performing press forming simulation of a blank based on CAD data;
A springback analysis unit that performs springback analysis based on the result of the press forming simulation;
A setting unit configured to set a position at which shape change processing is performed for measures against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and a model generation unit for generating a model of an influence area having a predetermined distance from an outer edge of the processing area;
A processing area stress calculation unit that performs stress calculation of the processing area based on a model of the processing area;
A synthesis unit that synthesizes data of stress as a result of the press forming simulation and data of stress as a result of stress calculation of the processing area;
An influence area stress calculation unit that performs stress calculation of the influence area based on a model of the influence area;
The springback analysis unit newly performs springback analysis based on the data of the stress synthesized by the synthesis unit and the data of the stress as a result of the stress calculation of the affected area.
It is characterized by

  According to this aspect, the data of the stress of the processing area calculated by the processing area stress calculation unit and the data of the stress of the influence area calculated by the influence area stress calculation unit are used as the data of the stress as a result of the press forming simulation. Springback analysis is newly performed based on the synthesized and synthesized stress data. Therefore, when processing the shape change as a springback suppression measure, it is not necessary to perform the change work of CAD data and the strain incremental analysis again, and the springback suppression measure effect can be confirmed at high speed.

  Next, in another aspect of the simulation system for springback suppression design by shape change according to the present invention, the setting unit further sets a portion where the shape change is to be processed and a shape in the shape change. According to the input, a shape type, a calculation type of stress data as a result of the stress calculation of the processing area, and an effect magnification are set for each of the portions where the processing of the shape change is to be performed. Do.

  According to this aspect, it is possible to simultaneously consider the specification of the location where the shape change is to be performed, the addition / subtraction effect of the shape, and the degree of the effect.

  Next, in another aspect of the simulation system for springback suppression design by shape change according to the present invention, the model creation unit is configured to locally generate data of the shape whose shape is changed, data of the original shape, and the influence. A model of the change area and the influence area is created on the basis of data of an outline defining the area and a shape database defining data of distortion generated by shape deformation.

  According to this aspect, when performing the spring back suppression measures, various shapes can be easily utilized. In the shape database, distortion or stress corresponding to the processing of the shape is not registered, but only the parameters for creating the shape are registered, so the size of the shape can be freely changed. It is possible.

  Next, in another aspect of the simulation system for springback suppression design by shape change according to the present invention, the model creation unit is configured to locally generate data of the shape whose shape is changed, data of the original shape, and the influence. A model of the processing area and the influence area is created on the basis of data of an outline defining the area and a shape database defining data of strain generated by shape deformation.

  According to this aspect, since the stress is calculated based on the model of the processing area and the influence area, it is necessary to perform the change work of the CAD data and the strain incremental analysis again when processing the shape change as a springback suppression measure. The effect of suppressing springback can be confirmed at high speed.

  Next, another aspect of the simulation system for springback suppression design by shape change according to the present invention is characterized in that the shape includes a shape freeze bead or an emboss.

  According to this aspect, it is not necessary to perform the change work of CAD data and the incremental strain analysis again by processing the shape change of the shape freezing bead or the emboss, and it is possible to confirm the springback suppression countermeasure effect at high speed.

  Next, another aspect of the simulation system for springback suppression design by shape change according to the present invention is that the press forming simulation unit or the springback analysis unit performs processing using isogeometric data. It features.

  According to this aspect, by using the data for IGA, the data output as a result of the press forming simulation or the spring back analysis can be used as a CAD surface attached to the mold as it is.

Next, one aspect of a simulation method for springback suppression design by shape change according to the present invention is:
Performing press forming simulation of the blank based on the CAD data;
Performing springback analysis based on the result of the press forming simulation;
Setting a position to be subjected to shape change processing for countermeasure against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and creating a model of an influence area having a predetermined distance from an outer edge of the processing area;
Performing stress calculation of the processing area based on the model of the processing area;
Combining the data of stress as a result of the press forming simulation and the data of stress as a result of stress calculation of the processing area;
Performing stress calculation of the affected area based on the model of the affected area;
Performing a springback analysis anew on the basis of the data of the stress synthesized in the synthesizing step and the data of the stress as a result of the stress calculation of the affected area.
It is characterized by

  According to this aspect, the data of the stress of the processing area calculated by the processing area stress calculation unit and the data of the stress of the influence area calculated by the influence area stress calculation unit are used as the data of the stress as a result of the less forming simulation. Springback analysis is newly performed based on the synthesized and synthesized stress data. Therefore, when processing the shape change as a springback suppression measure, it is not necessary to perform the change work of CAD data and the strain incremental analysis again, and the springback suppression measure effect can be confirmed at high speed.

Next, one aspect of a program in a simulation system for springback suppression design by shape change according to the present invention is:
A program in a simulation system for springback suppression design by shape change, the program comprising:
Performing press forming simulation of the blank based on the CAD data;
Performing springback analysis based on the result of the press forming simulation;
Setting a position to be subjected to shape change processing for countermeasure against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and creating a model of an influence area having a predetermined distance from an outer edge of the processing area;
Performing stress calculation of the processing area based on the model of the processing area;
Combining the data of stress as a result of the press forming simulation and the data of stress as a result of stress calculation of the processing area;
Performing stress calculation of the affected area based on the model of the affected area;
Performing a springback analysis step anew based on the data of the stress synthesized in the synthesizing step and the data of the stress as a result of the stress calculation of the affected area;
It is characterized by

  According to this aspect, the data of the stress of the processing area calculated by the processing area stress calculation unit and the data of the stress of the influence area calculated by the influence area stress calculation unit are used as the data of the stress as a result of the less forming simulation. Springback analysis is newly performed based on the synthesized and synthesized stress data. Therefore, when processing the shape change as a springback suppression measure, it is not necessary to perform the change work of CAD data and the strain incremental analysis again, and the springback suppression measure effect can be confirmed at high speed.

  According to the present invention, it is possible to simultaneously consider the identification of the location to which the shape change is to be made and the effect of the shape change, and to eliminate trial and error and rework. In addition, since calculation can be performed in a virtual design state, work time and calculation cost can be significantly reduced.

It is a block diagram showing composition of a simulation system for springback control design by shape change concerning one embodiment of the present invention. It is a block diagram which shows the structure of a processing apparatus. It is a block diagram which shows the structure of a memory | storage device. It is a block diagram which shows the structure of a program memory | storage part. It is a block diagram which shows the structure of a data storage part. It is a figure which shows the data structure of material characteristic data. The data structure of analysis model shape definition data is shown, (A) shows the data structure of nodal point coordinate data, (B) shows the data structure of shell element configuration node data. It is a figure which shows the data structure of the initial stage stress data of a shell element. It is a figure which shows the data structure of process part definition data, (A) is a definition of the database to be used, (B) is definition data of process information, (C) is analysis control data. It is a figure which shows the data structure of intermediate data. It is a figure which shows the data structure of intermediate data. It is a figure which shows the data structure of a shape database, (A) is nodal point coordinate data before shaping | molding, (B) is shell element structure node data before shaping | molding. It is a figure which shows the data structure of a shape database, (A) is the nodal point coordinate data after shaping | molding, (B) is shell element structure node data after shaping | molding. It is a figure which shows the data structure of a shape database. It is a figure which shows the data structure of a shape database. It is an outline flow chart of simulation for spring back control design by shape change. It is a flowchart which shows the detail of the effect introduction process to the blank material before spring back. It is a flowchart which shows the detail of model creation processing of a process area | region and an influence area | region. It is a flowchart which shows the detail of stress calculation processing of a process area | region. It is a flowchart which shows the detail of the synthetic | combination process of stress data. It is a flowchart which shows the detail of the stress calculation process of an influence area | region. It is a perspective view which shows an example of a shape freezing bead. It is a perspective view which shows an example of a shape freezing bead. It is a perspective view showing an example of embossing. (A) is a figure which shows the shape of the process area | region before a process, (B) is a figure which shows the shape of the embossing after a process. It is a figure for demonstrating an outline. It is a figure for demonstrating an interpolation surface. (A) is a view showing a shape obtained by performing an interpolation calculation to fit the interpolation surface by adding an influence area to the shape of the processing area before processing, and (B) adding an influence area to the shape of the emboss after processing; It is a figure which shows the shape which performed the interpolation calculation made to fit an interpolation surface. It is the figure which showed the position which opens a hole in an original model by the outline. FIG. 2 is a diagram showing a new model 1; FIG. 6 is a diagram showing a new model 2; It is a figure which shows the procedure of the effect introduction process of type 1. It is a figure which shows the relationship between stress and distortion. It is a figure which shows the procedure of the effect introduction process of type 2. It is a figure which shows the relationship between stress and distortion. It is a figure which shows the relationship between stress and distortion. (A) is the figure which looked at the state which original model produced springback deformation from the side, and (B) is the figure which looked at the state where original model generated springback deformation from the upper surface. (A) shows an original model in which the embossing process is not performed, (B) shows a state in which the type 1 process is performed, and (C) shows the type 2 process. It is a figure which shows a state. It is a perspective view which shows the state in which the process of Type 1 was performed. (A) is a table | surface which shows the displacement and reduction rate at the time of processing Type 1, (B) is a table | surface which shows the displacement and reduction rate when processing Type 2 is performed.

  A simulation system for springback suppression design by shape change according to an embodiment of the present invention will be described with reference to the drawings. The simulation system for springback suppression design by shape change of this embodiment is the stress data of the processing area of the shape change and the influence area in the original stress data as a result of the press forming simulation for the springback suppression. It is a system that combines stress data and performs springback analysis.

(1) Outline of Simulation System for Springback Suppression Design by Shape Change FIG. 1 is a block diagram showing a configuration of a simulation system 10 for springback suppression design by shape change according to an embodiment of the present invention. .

  The simulation system 10 is a computer such as a personal computer as an example. As shown in FIG. 1, the simulation system 10 includes a processing device 11 such as a CPU, a storage device 12 such as a memory or a hard disk, an input device 13 such as a keyboard, a mouse or a CD-ROM drive, a liquid crystal display or a printer And an output device 14 of

(1-1) Processing Apparatus FIG. 2 is a block diagram showing a configuration of the processing apparatus 11 of FIG.

  As shown in FIG. 2, the processing apparatus 11 includes a press forming simulation unit 110, a springback analysis unit 120, a setting unit 130, an effect introduction control unit 135, a model generation unit 140, and a processing area stress calculation unit 145. , A synthesis unit 150, and an influence area stress calculation unit 160.

  The press forming simulation unit 110 performs press forming simulation by the finite element method using shape data of a product to be press molded such as CAD data and data for press forming simulation such as shell element data and material property data. . The press forming simulation unit 110 may perform press forming simulation using data for isogeometric analysis (hereinafter referred to as IGA) instead of shell element data. The data for IGA is, for example, data obtained by converting CAD data into data for IGA. By using the data for IGA, the data output as a result of the press forming simulation can be used as a CAD surface attached to the mold as it is.

  The springback analysis unit 120 performs a springback analysis based on a change in plate thickness in the product shape state, a plastic strain, and six components of stress obtained as a result of press forming simulation by the press forming simulation unit 110. Further, in the present embodiment, the springback analysis is performed also after the effect of the shape change is introduced to the data of the product shape by the press forming simulation. Details will be described later. The springback analysis unit 120 may perform springback analysis using data for IGA instead of shell element data. By using data for IGA, data output as a result of springback analysis can be used as a CAD surface attached to a mold as it is.

  The setting unit 130 sets a location to be changed in shape, a processing type, and a shape according to an input from the user. Details will be described later.

  The effect introduction control unit 135 performs predetermined processing in the effect introduction process by the shape change. Details will be described later.

  The model creation unit 140 creates a model formed by the process of shape change. The model to be created varies depending on the processing type. Details will be described later.

  The processing area stress calculation unit 145 calculates the stress in the processing area. Details will be described later.

  The synthesizing unit 150 synthesizes the original stress data by the press forming simulation, the stress data of the processing area by the shape change, and the stress data of the affected area. Details will be described later.

  The affected area stress calculation unit 160 calculates the stress in the affected area. Details will be described later.

(1-2) Storage Device FIG. 3 is a block diagram schematically showing a configuration of the storage device 12 of FIG. As shown in FIG. 3, the storage device 12 mainly includes a program storage unit 12A, a data storage unit 12B, and a shape database 12C.

FIG. 4 is a block diagram schematically showing a configuration of program storage unit 12A of FIG. As shown in FIG. 4, the program storage unit 12A stores program storage units 12A _{1 to} 12A ₃ that store a press forming simulation program PR1, a springback analysis program PR2, and an effect introduction program PR3 for a pre-springback blank material. Have.

FIG. 5 is a block diagram schematically showing a configuration of data storage unit 12B of FIG. As shown in FIG. 5, the data storage unit 12B stores press forming simulation data DT1, material characteristic data DT2, springback analysis data DT3, processing portion definition data DT4, intermediate data DT5, and model data DT6, respectively. the data storage unit _12B 1 _{~12B 6} has.

Here, FIGS. 6 to 15 show data configurations of the data DT2 to DT5 described above. The data structures of the press forming simulation data DT1 and the model data DT6 are not shown. Hereinafter, with reference to FIGS. 6 to 15, it will be described in detail data DT2~DT5 stored in the data storage unit _12B 2 _{~12B 5.}

(1-2-1) Material Property Data The material property data DT2 is data defining the elasto-plastic property of the processed material. For example, as shown in FIG. 6, in addition to Young's modulus E and Poisson's ratio 示 す, which show the characteristics as an elastic material, yield stress σy and power law K are given as an example of defining distortion / stress characteristics after plasticization. There are values, n values, etc. There are various types other than this example, such as defining function type and curve by point sequence. In the present embodiment, power property type material property data is described as an example.

(1-2-2) Springback Analysis Data Springback analysis data DT3 is data for springback analysis obtained as an output of press forming simulation. In the present embodiment, it is also called original data. As an example of the spring back analysis data DT3, FIG. 7 shows analysis model shape definition data, and FIG. 8 shows initial stress data of shell elements. FIG. 7A shows nodal point coordinate data, and FIG. 7B shows shell element constituent node data. In this embodiment, springback analysis is performed using the output by the exact incremental analysis method using the finite element method based on such data DT3 for springback analysis.

(1-2-3) Machining part definition data The machining part definition data DT4 is the selection of the shape of the bead or the like to be machined to change the shape, the data on the position and the direction, and the analysis method used on the system of this embodiment. And data that defines parameter values and the like necessary for Further, the processing part definition data DT4 includes data for defining the area of the processing part and the influence area where the stress distribution is smoothed. The area of the processing unit is a range in which the mesh shape is replaced. The affected area is the area affected by the stress value when the emboss or bead is processed.

  FIG. 9A is a definition of a database to be used, and FIG. 9B is definition data of processing information. FIG. 9C shows analysis control data, and the total number NCH of machining positions is the same as FIG. 9B.

(1-2-4) Intermediate Data The intermediate data DT5 is data temporarily used in the system of this embodiment. Each processing unit includes a coordinate conversion matrix associated with the orientation of the main axis along with the selection of the database shape, and interpolation data for corresponding to the case where the corresponding area is not a plane but a curved surface. FIG. 10 shows coordinate conversion data, and the total number NCH of processing positions is common to processing portion definition data DT4. FIG. 11 shows curved surface area interpolation function data, and the total number NCH of processing positions is common to processing portion definition data DT4. In the example shown in FIG. 11, the interpolation plane shows nine points (square type) of quadratic interpolation, but there are other 16 points (cubic interpolation) and the like.

(1-2-5) Shape Database The shape database 12C is a database in which data for defining the shape of the shape freeze bead or emboss locally processed by shape change and the original shape is stored. In addition, in the shape database 12C, data in which distortion generated by the shape change is defined is stored. In the present embodiment, the format of data stored in the shape database 12C is the same as the format of data for analysis by the finite element method. However, the format of the data is not limited to such an aspect, and can be determined by a plurality of means such as a strict incremental analysis method by the finite element method, a simple one-step method, or a theoretical solution method. .

  The shape database 12C is managed by the name of the database according to the type of shape freezing bead or embossing, and each database can be selected by specifying the name. The number of types of shape freezing beads and emboss types is arbitrary, and addition, deletion, etc. are possible. Also, the dimensions of the shape freezing beads and the emboss are defined in individual databases.

  12 to 15 show an example of data stored in the shape database 12C. FIG. 12 shows shape data before forming, FIG. 12 (A) shows nodal coordinate data, and FIG. 12 (B) shows shell element configuration nodal data. FIG. 13 shows shape data after forming, FIG. 13 (A) shows nodal coordinate data, and FIG. 13 (B) shows shell element configuration nodal data. FIG. 14 shows data of strain increment of each shell element by the shaping of the shape changer alone. FIG. 15 shows external configuration line data. Details of the outer configuration line will be described later.

(1-3) Input Device The input device 13 is used to input the various data described above, set various analysis conditions, or control the system.

(1-4) Output Device The output device 14 includes a display device such as a liquid crystal display, a printer, and the like. For example, on the display device, an input setting screen, an analysis result, CAD data in plane units, and a CAD data development view are graphically displayed in three dimensions.

(2) Outline of simulation for springback suppression design by shape change For the outline of simulation for springback suppression design by shape change of this embodiment, referring to the flowchart of FIG. 16 and FIGS. 22 to 34 explain.

As shown in FIG. 16, first, press forming simulation unit 110, using a press forming simulation data DT1 stored in the data storage unit 12B ₁ of the data storage unit 12B, carrying out the press-forming simulation (Fig. 16: S1). Press forming simulation unit 110 stores springback analysis data DT3 obtained as an output of the simulation (the original) in the data storing unit 12B ₃ of the data storage unit 12B.

  Next, the springback analysis unit 120 performs springback analysis with reference to the material characteristic data DT2 of the data storage unit 12B (FIG. 16: S2). The result of the springback analysis is displayed as a contour on a display device as the output device 14, for example.

  In the present embodiment, the user can select an arbitrary area on the image of the press-formed product displayed as a result of the press-forming simulation, and further, specify a magnification for the stress of the selected area. it can. The springback analysis unit 120 may change the stress of the selected area into a stress of a designated magnification to perform springback calculation. In addition, the springback analysis unit 120 may output the result of comparison of the springback calculation result in which the residual stress is the initial stress as it is with the springback calculation result in which the residual stress is partially changed to be the initial stress. it can. Such a springback analysis function allows the user to identify locations that have a significant impact on springback.

  The user refers to the result of the springback analysis, determines several places that greatly affect the springback, and designates the shape change area. Also, the user designates the type and size of shape change to be added to the shape change area, the type of shape change processing, and the effect magnification by the shape change. The setting unit 130 sets the shape change area, the type and size of shape change, the type of shape change processing, and the effect magnification as a design proposal according to the user's designation as described above (FIG. 16: S3). .

  Types of shape changes include shape freezing beads and embossing. An example of a shape freezing bead is shown in FIG. 22 and FIG. 23, and an example of embossing is shown in FIG. The shape freezing bead is a protrusion having a circular, oval or rectangular cross section, and has a shape freezing bead B1 having an oval cross section as shown in FIG. 22 or a shape having a rectangular cross section as shown in FIG. The freeze bead B2 is used. Besides this, shaped freezing beads having a triangular cross section are also used.

  The emboss is a circular, oval or rectangular flat plate provided with a concave shape having a circular, oval or rectangular cross section, for example, an embossed E1 having a shape similar to a plate as shown in FIG. Used.

  Types of shape change processing include Type 1 (additive type) in which a shape freeze bead or emboss is added to the shape change area, and a shape change area is returned to the original shape after the shape freeze bead or emboss is added There is a type 2 (addition / subtraction type). Details of Type 1 and Type 2 will be described later.

When the setting of the design proposal by the setting unit 130 is completed, the model creating unit 140, the combining unit 150, and the influence area stress calculating unit 160 perform the process of introducing the shape change effect to the pre-springback blank (FIG. 16: S4). Details of the introduction process of the shape change effect will be described using the flowchart of FIG. 17 described later. In the introduction process of the shape change effect,
The material characteristic data DT2 of the data storage unit 12B, the data for springback analysis DT3 (original), and the shape database 12C are referred to. Further, the result of the introduction process of the shape change effect is stored in the data storage unit 12B as spring back analysis data DT3 (after the shape change).

  When the process of introducing the shape change effect into the pre-springback material is completed, the springback analysis unit 120 uses the springback analysis data DT3 (after shape change) stored in the data storage unit 12B to perform springback again. Analysis is performed (FIG. 16: S5).

(Introduction processing of shape change effect to pre-springback blank)
Next, the details of the introduction process of the shape change effect to the pre-springback material will be described with reference to the flowchart of FIG. In the following description, as an example, the case where the type of shape change is an emboss E1 having a circular cross section (see FIG. 24) will be described.

  The model creating unit 140 reads out necessary data from the processing unit definition data DT4 (see FIG. 9) of the data storage unit 12B based on the setting of the design proposal by the setting unit 130, and sets the shape change condition (FIG. 17). : S10).

  The data storage unit 12B includes an identification number for identifying a shape database that defines the shape of an emboss to be used for each processing position as processing part definition data DT4, definition data of processing information in which processing types and the like are stored, and processing positions The analysis control data in which the shape interpolation type, the influence area type and the like are stored for each is stored. The model creating unit 140 sets shape change conditions based on the read definition data of the processing information and the analysis control data.

  Next, the model creating unit 140 reads out the shape database specified from the shape database 12C based on the shape change condition, and performs model creation processing of the processing area to be changed in shape and the influence area around it (FIG. 17: S11). The result of the model creation process is stored as intermediate data DT5 in the data storage unit 12B. The details of the processing for creating the processing area and the influence area will be described based on the flowcharts of FIGS. 18 and 19 described later. In addition, details of the processing area and the influence area will be described later.

  When the model creation processing of the processing area and the influence area is completed, the processing area stress calculation unit 145 performs stress calculation of the processing area with reference to the material characteristic data DT2 of the data storage unit 12B (FIG. 17: S12). The details of the stress calculation of the processing area will be described based on the flowchart of FIG. 20 described later.

  When the stress calculation of the processing area is completed, the synthesizing unit 150 refers to the spring back analysis data DT3 (original) of the data storage unit 12B and calculates the stress calculation of the processing area into the data of the stress of the original model before processing. The resulting stress data are synthesized (FIG. 17: S13).

  When the synthesis of the stress data is completed, the affected area stress calculation unit 160 performs stress calculation of the affected area with reference to the intermediate data DT5 in the data storage unit 12B (FIG. 17: S14). The details of the stress calculation in the affected area will be described based on the flowchart of FIG. 21 described later.

  The effect introduction control unit 135 determines whether or not the processing has been completed for all pieces of processing information, and when the processing has not been completed, shifts the processing to model creation processing by the model creation unit 140 in step S11. However, if it is determined that processing has been completed for all processing positions, data obtained by combining the stress data of the processing area with the stress data of the original model and stress data of the affected area are stored for all processing positions. The data is stored as springback analysis data DT3 (after shape change) of the portion 12B (FIG. 17: S15).

(Modeling process of machining area and influence area)
Next, with reference to the flowchart of FIG. 18 and FIG. 25 to FIG. 28, details of the model creation processing of the change area and the influence area will be described.
The model creating unit 140 reads out the database name of the shape database from the identification number of the shape database included in the processing information of the processing part definition data DT4, and the shape data and outline before and after processing from the database of the database name from the shape database 12C. Line data is acquired (FIG. 18: S20). In the case of the emboss E1, for example, the shape shown in FIG. 25 (A) is the shape 1 before processing, and the shape shown in FIG. 25 (B) is the shape 2 of the emboss E1 after processing.

  The outline data is data of the outline 1 before processing, the shape 2 after processing, and the outline of the affected area. An example of an outline is shown in FIG. In FIG. 26, the outline of the shape 1 before processing is shown as the outline 1, and the outline of the shape 2 after processing is shown as the outline 2. Further, an outline of an influence area separated from the outline 2 by a predetermined interval s1 in the X-axis direction and separated by a predetermined interval s2 in the Y-axis direction is shown as an outline 3.

  The affected area is a peripheral area that is affected by the stress value when emboss, shape freezing bead, etc. are processed. In this embodiment, such an influence area is provided around the processing area in which the shape change processing is performed, and the effect of the shape change processing is enlarged.

  Next, the model creating unit 140 enlarges or reduces the shape 2 after processing based on magnification data in the X-axis direction, the Y-axis direction, and the Z-axis direction included in the processing information of the processing part definition data DT4. The outline line data and the interpolation plane data of the shape 2 enlarged or reduced are created (FIG. 18: S21).

  Interpolation plane data is data defining an interpolation plane to cope with the case where the processing area is not a plane but a curved surface. In this embodiment, as shown in FIG. 27, the interpolation surface is a surface of an area determined by four points of Xmin, Xmax, Ymin, and Ymax, and the interpolation surface data includes the four points and is included in this area. It is data of quadratic interpolation composed of data of 9 points (in square shape). However, interpolation surface data usable in the present invention is not limited to such an aspect, and may be data of cubic interpolation composed of data of 16 points.

  The model creating unit 140 stores the created outline data and the interpolation plane data in the data storage unit 12B as intermediate data DT5.

  The model creating unit 140 refers to the springback analysis data DT3 and the processing information definition data of the processing portion definition data DT4, and calculates the coordinates of the setting center point of the emboss and the normal vector of the setting center point. (FIG. 18: S22).

  The model generation unit 140 calculates a coordinate conversion matrix for conversion from the emboss coordinate system to the original model coordinate system (FIG. 18: S23). The model creating unit 140 stores the calculated coordinate transformation matrix in the data storage unit 12B as intermediate data DT5.

  The model generation unit 140 performs coordinate conversion on the interpolation surface definition point, and projects the original model in the normal direction (FIG. 18: S24).

  The model creating unit 140 performs interpolation calculation to fit the shape 1 ′ and the shape 2 ′ obtained by adding the affected area to the shape 1 before processing and the shape 2 after processing, to shape 1 ′ ′ and 2 ′ ′. Are created (FIG. 18: S25), and the model creation processing of the processing area and the influence area is finished. Fig. 28 (A) shows the shape 1 ', and Fig. 28 (B) shows the shape 2'.

(Calculation of stress in machining area)
Next, the details of the stress calculation of the processing area shown as step S12 in the flowchart of FIG. 17 will be described with reference to FIG.

  The processing area stress calculation unit 145 refers to the data of springback analysis data (original) DT3 and data of the new model 1 of the model data DT6, and applies the original stress distribution to the corresponding element (mesh) of the new model 1 Mapping is performed in the entire coordinate system (FIG. 19: S30).

  The new model 1 is different in mesh division from the original but uses the shape before molding, so it is considered to be almost the same as the original, and simply judged from the positional relationship, the stress value of the element of the original data is considered. Get and set.

  The machining area stress calculation unit 145 converts the strain increment registered in the shape database 12C into the entire coordinate system with reference to the shape database 12C and the intermediate data DT5 (FIG. 19: S31). The strain increment registered in the shape database is determined by the direction depending on the mounting position because it is a coordinate system in which the main spindle 1 and the main spindle 2 receive forming in the Z direction with respect to a two-dimensional plane in the X and Y directions. It is because it is necessary to convert to a coordinate system.

  The processing area stress calculation unit 145 converts the stress component before forming and the component of the strain increment due to forming into the corresponding element coordinate system with reference to the shape database 12C and the intermediate data DT5 (FIG. 19: S32).

  The processing area stress calculation unit 145 refers to the material characteristic data DT1 to calculate the stress component after forming due to strain increase in the element coordinate system (FIG. 19: S33).

  Next, the processing area stress calculation unit 145 determines whether the processing type is type 1 or type 2. If the processing type is type 2, referring to the material characteristic data DT1, after forming due to strain reduction The stress component of is calculated in the element coordinate system (FIG. 19: S34).

  Next, when it is determined that the processing type is type 1 or after the calculation of the stress component after forming due to strain reduction is completed, the processing area stress calculation unit 145 reverses the stress after processing to the entire coordinate system. It converts and it is set as the stress of the element applicable to each of the new model 1 and the new model 2 (FIG. 19: S35).

  Since the update of stress is performed by the element coordinate system, each component is temporarily converted from the entire coordinate system to the element coordinate system, the stress after forming is calculated, and then converted back to the entire coordinate form by inverse transformation. In the coordinate conversion, the shapes of the new model 1 and the new model 2 are different.

  The machining area stress calculation unit 145 determines whether or not each process described above has been completed for all of the target elements, and if not completed, repeats the process from step S30 to step S34. However, if it is determined that the above-described processing has been completed for all of the target elements, the stress calculation processing of the processing area is completed.

(Composition processing of stress data)
Next, details of the stress data combining process shown as step S13 in the flowchart of FIG. 17 will be described with reference to the flowchart of FIG. 20 and FIGS.

  After trimming the original model with the shape 1 ′ ′, the combining unit 150 creates the new model 1 by combining the shape 1 ′ ′ with the original model (FIG. 20: S40). Here, "trimming" means making holes in the original model by the outline 3 as shown in FIG. 29, and "combining" means filling the holes with their respective shapes and joining the meshes in the periphery. It means that.

  The data of the new model 1 is stored as model data DT6 in the data storage unit 12B. The new model 1 is a model in which all the processing regions are changed to the shape 1. The new model 1 is a model used before processing and when the processing type is type 2. An example of the new model 1 is shown in FIG.

  The model creating unit 140 determines whether the processing type is type 1 or type 2. If the processing type is type 2, the process ends. However, in the case of type 1, the model creating unit 140 creates the new model 2 by trimming the original model with the shape 1 ′ ′ and then combining the shape 2 ′ ′ with the original model (FIG. 20: S41) ), End the stress data synthesis process. The new model 2 is a model in which the processing type is changed to the shape 2 only in the processing region of type 1 with respect to the new model 1. An example of the new model 2 is shown in FIG.

(Stress calculation process of influence area)
Next, with reference to the flowchart of FIG. 21, the details of the stress calculation process of the affected area shown as step S14 in the flowchart of FIG. 17 will be described.

  Affected area stress calculation unit 160 determines whether the processing type is type 1 or type 2 and, in the case of type 1 (see FIG. 31), within the affected area between outline 2 and outline 3 For the element, the stress component is an average value of both sides (FIG. 21: S50).

  When the processing type is type 2 (see FIG. 30), the influence area stress calculation unit 160 averages stress components on both sides with respect to elements in the influence area between the outline 1 and the outline 3. It is assumed (FIG. 21: S51).

    Affected area stress calculation unit 160 determines whether or not the process of step S50 or step S51 is completed for all target elements in the affected area, and if not completed, the process of step S50 or step S51 is performed. Repeat the process. However, if it is determined that the process of step S50 or step S51 is completed for all the target elements in the influential area, the stress calculation process of the influential area is ended.

(Procedure of effect introduction process of type 1)
Next, with reference to FIG. 32, the procedure of the above-described effect introduction process when the processing type is type 1 will be described.

  FIG. 32 (1) shows a stress distribution (original stress distribution) without emboss and the like obtained as a result of the press forming simulation shown in step S1 of FIG. The original stress distribution has six components of σ (x, y) in the element coordinate system, σxx, σyy, σzz, τxy, τyx, and τzx, for each element (mesh) of FEM. An area indicated by a dotted line in FIG. 32 (1) indicates a processing area defined by the outline 3.

  Next, FIG. 32 (2) maps the original stress distribution in the entire coordinate system to the corresponding element (mesh) in the processing area shown in step S12 of FIG. 17 and step S30 of FIG. Processing is shown.

  Next, in FIG. 32 (3), a new model 2 of the processing area and the influence area shown in step S11 of FIG. 17 and FIG. 18 is created, and thereafter, at the time of molding shown in step S12 of FIG. Shows the process of performing the strain increment calculation of. Molding can be performed by a theoretical formula, an approximate formula, or a one-step method, and in this embodiment, molding is performed by a one-step method as an example.

  Next, FIG. 32 (4) shows a process of calculating a stress component after forming due to a strain increase shown in step S34 of FIG. Assuming that the original stress is σ (original) and the strain increment is F (Δε), the stress component σ (update) after forming is expressed by the following equation.

σ (update) = σ (original) + F (Δε)

  FIG. 33 is a graph showing the relationship between stress σ and strain ε. (2), (3) and (4) shown in FIG. 33 correspond to (2), (3) and (4) in FIG. As shown in FIG. 33, the stress after forming increases from the original stress by a strain increment.

  FIG. 32 (4) shows a process of combining the new model 2 after trimming the original model with the shape 2 ′ ′ shown in step S13 of FIG. 17 and FIG.

  As described above, when the processing type is type 1, the stress of the processed portion including the affected area is added to the stress of the original model in which the processing area is drilled, and the stress of the synthesized model is obtained.

(Procedure of effect introduction processing of type 2)
Next, with reference to FIGS. 34 to 36, the procedure of each effect introduction process described above in the case where the processing type is type 2 will be described.

  FIG. 34 (1) shows a stress distribution (original stress distribution) in a state without embossing or the like obtained as a result of the press forming simulation shown in step S1 of FIG. The original stress distribution has six components of σ (x, y) in the element coordinate system, σxx, σyy, σzz, τxy, τyx, and τzx, for each element (mesh) of FEM. An area indicated by a dotted line in FIG. 34 (1) indicates a processing area defined by the outline 3.

  Next, FIG. 34 (2) maps the original stress distribution in the entire coordinate system to the corresponding elements (meshes) in the processing area shown in step S12 in FIG. 17 and step S30 in FIG. Processing is shown.

  Next, in FIG. 34 (3), the new model 1 and the new model 2 of the machining area and the influence area shown in step S11 of FIG. 17 and FIG. 18 are created, and then in step S12 of FIG. The process which performs the distortion increment calculation at the time of shaping | molding shown is shown. Molding can be performed by a theoretical formula, an approximate formula, or a one-step method, and in this embodiment, molding is performed by a one-step method as an example.

  Next, FIG. 34 (4)-1 shows a process of calculating a stress component after forming due to a strain increase shown in step S 34 of FIG. 19. Assuming that the original stress is σ (original) and the strain increment is F (Δε), the stress component σ (update-1) after forming is expressed by the following equation.

σ (update-1) = σ (original) + F (Δε)

  FIG. 35 is a graph showing the relationship between stress σ and strain ε. (2), (3), (4) -1 shown in FIG. 35 correspond to (2), (3), (4) -1 in FIG. As shown in FIG. 35, the stress after forming increases from the original stress by a strain increment.

  Next, FIG. 34 (4)-2 shows a process of calculating a stress component after forming by strain reduction shown in step S 33 of FIG. 19. When the processing type is type 2, the processing area is once processed into type 1, and then returned to the original shape. Thus, the strain is reduced. Assuming that this strain reduction is −F (Δε), a stress component σ (update-2) after forming of type 2 is expressed by the following equation.

σ (update-2) = σ (update-1) -F (Δε)

  FIG. 36 is a graph showing the relationship between stress σ and strain ε. (2), (3), (4) -1, and (4) -2 shown in FIG. 36 correspond to (2), (3), (4) -1, and (4) -2 in FIG. doing. As shown in FIG. 36, the stress after molding of Type 2 is reduced from the stress after molding of Type 1 by the amount of strain reduction.

(Example)
Next, an embodiment will be described with reference to FIGS. 37 to 40. FIG. 37A is a side view of the original model in a state in which a springback deformation occurs. Uz represents displacement. FIG. 37B is a top view of the original model in a state in which springback deformation occurs. A, B and C of FIG. 37 (B) show the attachment positions of the emboss.

  FIG. 38 (A) shows an original model in which the embossing process is not performed, FIG. 38 (B) shows a state in which the type 1 process is performed, and FIG. 38 (C) shows the type 2 It is a figure which shows the state in which the process of (1) was performed. FIG. 39 is a perspective view showing a state in which processing of type 1 has been performed.

  FIG. 40 (A) is a table showing the displacement Uz and the reduction rate when processing of type 1 is performed. FIG. 40 (B) is a table showing displacement Uz and reduction rate when processing of type 2 is performed. As shown in FIG. 40 (A), the displacement Uz of the original model not subjected to embossing was 71.6 mm.

(For type 1 processing)
As shown to FIG. 40 (A), when the process of Type 1 was performed to the location of A, the displacement Uz became 55.1 mm and the reduction rate was 23.0%. When Type 1 processing was performed on the portion B, the displacement Uz was 60.2 mm, and the reduction rate was 15.9%. When Type 1 processing was performed on the portion C, the displacement Uz was 65.3 mm, and the reduction rate was 8.89%. And when processing of type 1 was performed to three places of A, B, and C, displacement Uz was set to 39.6 mm, and a reduction rate was 44.7%. Therefore, in this case, it is understood that when the type 1 processing is performed at three locations A, B and C, the spring back deformation can be suppressed most.

(In the case of type 2 processing)
As shown in FIG. 40 (B), when Type 2 processing was performed on the part A, the displacement Uz was 59.0 mm, and the reduction rate was 17.6%. In the case where an emboss processed by type 2 was provided at the portion B, the displacement Uz was 59.4 mm, and the reduction rate was 17.0%. When Type 2 processing was performed on the portion C, the displacement Uz was 70.9 mm, and the reduction rate was 0.98%. And when processing of type 2 was performed to three places of A, B, and C, displacement Uz was set to 48.0 mm, and a reduction rate was 33.0%. Therefore, in this case, it is understood that when the type 2 processing is performed at three locations of A, B and C, the spring back deformation can be suppressed most.

  In addition, when all the results are examined, it can be seen that, in this example, when Type 1 processing is performed at three locations A, B, and C, springback deformation can be minimized.

  As mentioned above, according to the simulation system for springback suppression design by shape change of this embodiment, when processing of shape change is performed as springback suppression measures, the change work of CAD data and the strain incremental analysis are again performed. There is no need to do it, and it is possible to confirm the effect of springback suppression at high speed.

  In addition, according to the system of the present embodiment, the shapes such as the shape freezing bead and the emboss are registered in advance in the shape database and used. When taking measures against springback, various shapes can be easily used. it can. In addition, distortion or stress corresponding to the processing of the shape is not registered in the shape database, and only parameters for creating the shape are registered, so that the size of the shape can be freely changed. It is possible to

  In the system of the present embodiment, it is possible to perform calculation that incorporates the shape change effect at high speed using the one-step method. Therefore, it is possible to simultaneously consider the identification of the location where the shape change is to be performed, the addition / subtraction effect of the shape, and the degree of the effect.

  In the system of the present embodiment, in order to add the shape by addition as an actual model, it is possible to consider composition (resistance to deformation) by the shape. Also, the shape freezing bead and the accuracy of the embossing effect can be adjusted depending on the degree of modeling, that is, whether it is a detailed model or a simple model.

  In the system of this embodiment, it is also possible to use an IGA element, and it can be used as a CAD surface attached to a mold as it is. In the system of this embodiment, calculation of stress distribution can be performed by both FEM and IGA.

  As mentioned above, the present invention may be suitably used in the field of springback analysis by CAE.

10: simulation system 110: press forming simulation unit 120: springback analysis unit 130: setting unit 135: effect introduction control unit 140: model creation unit 145: processing area stress calculation unit 150: synthesis unit 160: influence area stress calculation unit

Claims (7)

A press forming simulation unit for performing press forming simulation of a blank based on CAD data;
A springback analysis unit that performs springback analysis based on the result of the press forming simulation;
A setting unit configured to set a position at which shape change processing is performed for measures against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and a model generation unit for generating a model of an influence area having a predetermined distance from an outer edge of the processing area;
A processing area stress calculation unit that performs stress calculation of the processing area based on a model of the processing area;
A synthesis unit that synthesizes data of stress as a result of the press forming simulation and data of stress as a result of stress calculation of the processing area;
An influence area stress calculation unit that performs stress calculation of the influence area based on a model of the influence area;
The springback analysis unit newly performs springback analysis based on the data of the stress synthesized by the synthesis unit and the data of the stress as a result of the stress calculation of the affected area.
Simulation system for springback suppression design by shape change characterized by that. The setting unit sets the shape type, the processing area, for each of the portions to be subjected to the processing of the shape change according to the input after setting the portion to perform the shape change processing and the shape in the shape change. Set the calculation type of stress data as a result of stress calculation of, and effect magnification,
The simulation system for springback suppression design by shape change according to claim 1. The model creation unit is based on a shape database that defines locally changed data of the shape, data of the original shape, data of the outline defining the affected area, and data of strain generated by shape deformation. Creating a model of the processing area and the influence area,
The simulation system for springback suppression design by shape change according to claim 1 or claim 2. Said shapes include shape freezing beads or embossments,
The simulation system for springback suppression design by shape change according to any one of claims 1 to 3 characterized by the above-mentioned. The press forming simulation unit or the springback analysis unit performs processing using isogeometric data.
The simulation system for springback suppression design by shape change according to any one of claims 1 to 4 characterized by the above-mentioned. Performing press forming simulation of the blank based on the CAD data;
Performing springback analysis based on the result of the press forming simulation;
Setting a position to be subjected to shape change processing for countermeasure against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and creating a model of an influence area having a predetermined distance from an outer edge of the processing area;
Performing stress calculation of the processing area based on the model of the processing area;
Combining the data of stress as a result of the press forming simulation and the data of stress as a result of stress calculation of the processing area;
Performing stress calculation of the affected area based on the model of the affected area;
Performing a springback analysis anew on the basis of the data of the stress synthesized in the synthesizing step and the data of the stress as a result of the stress calculation of the affected area.
Simulation method for springback suppression design by shape change characterized by the above. A program in a simulation system for springback suppression design by shape change, the program comprising:
Performing press forming simulation of the blank based on the CAD data;
Performing springback analysis based on the result of the press forming simulation;
Setting a position to be subjected to shape change processing for countermeasure against spring back deformation based on the result of the spring back analysis and a shape in the shape change according to an input;
A processing area for processing the shape change, and creating a model of an influence area having a predetermined distance from an outer edge of the processing area;
Performing stress calculation of the processing area based on the model of the processing area;
Combining the data of stress as a result of the press forming simulation and the data of stress as a result of stress calculation of the processing area;
Performing stress calculation of the affected area based on the model of the affected area;
Performing a springback analysis step anew based on the data of the stress synthesized in the synthesizing step and the data of the stress as a result of the stress calculation of the affected area;
A program in a simulation system for springback suppression design by shape change characterized in that.

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