JP2019175105A - Die deflection model creation system and die deflection model creation program - Google Patents

Abstract

To create a die deflection model capable of performing analysis with excellent precision while restraining the increasing number of man-hours.SOLUTION: A die deflection model creation system in an analysis model of a die for analyzing press forming using a press forming die by a finite-element method, and that comprises: a fine mesh surface shell model acquisition section 210 for acquiring a fine mesh surface shell model that is a fine mesh made up of shell elements in an elastic body without rigidity as a surface model of a deflection consideration die required for considering deflection, from either of the dies; a hoarse mesh solid model creation section 220 for creating a hoarse mesh solid model that is a hoarse mesh of the deflection consideration die made up of solid elements in an elastic body; and an adhesive surface creation section 230 for bonding the surface of the hoarse mesh solid model and the fine mesh surface shell model by a prescribed contact condition.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a mold deflection model creation system and a mold deflection model creation program for performing a press molding analysis by a finite element method in consideration of the deformation of a die for a press-molded product, and particularly a computer-aided design support. The present invention relates to a system and a program used for the system.

  For example, a panel component constituting an automobile body or the like is manufactured from a sheet metal as a raw material by press molding using a press molding die (hereinafter referred to as “mold”). In press molding, in order to predict the occurrence of defects such as cracks, wrinkles, and poor dimensional accuracy in the molded product during molding, a mold analysis model is created at the stage of mold design and development, and A simulation is being performed.

  In recent years, there has been a demand for more accurate prediction of such defects during press forming, and for this purpose, press forming simulation capable of more accurate analysis is required.

  As an example of such press molding, by pressing a material (blank material) into a cavity formed in a die with a punch while sandwiching the periphery by a die and a blank holder (hereinafter simply referred to as “holder”), There is a drawing method for drawing.

  In drawing, as shown in FIG. 32, the holder H is supported by a plurality of cushion pins Hp (hereinafter simply referred to as “pins”) extending downward in the vertical direction, and an upward cushion force (wrinkle holding force). ). Further, by providing the squeezing beads Hb and Db at appropriate positions of the holder H and the die D while considering the cushioning force, the material B flowing into the cavity C by the punch P in the direction opposite to the inflow direction. The inflow balance of the material B is adjusted by applying resistance.

However, in reality, the resultant force of the reaction force F _{1 of the} resistance force and the reaction force F ₂ of the cushion force is applied to the holder H, so that the upper end of the pin Hp bends inward as shown by the broken line in FIG. Deformation occurs in which the inner part of the holder H supported by the pin Hp bends in the direction opposite to the pressing direction.

  Since the deflection amount of the holder H at this time greatly affects the inflow balance of the material, it is important to reproduce the deflection of the holder H in the simulation in order to improve the analysis accuracy of the simulation. In some cases, it is important to reproduce the deflection of the die D and the punch P during the simulation.

  However, in the conventional press molding simulation, the analysis model of the mold including the holder H, the die D, and the punch P is defined as a rigid shell model that does not deform. The simulation considering deformation could not be performed.

  Therefore, in order to perform a simulation considering the deformation of the mold, for example, as disclosed in Non-Patent Document 1, the mold is modeled with a rigid shell element as in the prior art, and the bottom dead center of the mold. A method is employed in which the deflection amount of the holder H is calculated by static stress analysis, and the calculated deflection amount is mapped to each shell element for reanalysis. Further, as disclosed in Non-Patent Documents 2 and 3, there is a method of modeling the entire mold with a solid element that is a deformable elastic body and analyzing the deformation of the mold in the middle of molding while sequentially calculating it. It's being used.

Hideo Sasamori et al. 2, "Prediction of poor accuracy of 3D shape of thin sheet -Study on springback prediction by FEM 3rd report-", Plasticity and Processing, Vol. 44, No. 518, published on October 25, 2003, p . 1024-1028 Takamura Masato et al. 5, “Sheet Forming Simulation Considering Elastic Die Deformation by Static Explicit FEM”, Plasticity and Processing, Vol. 47, No. 540, published on January 25, 2006, p. 64-68 Ryonobu Ishiwatari et al. 3, “Effects of the modeling range of elastic bodies of dies and press machines on torsion springback prediction of bent hat materials”, Plasticity and Machining, Vol. 56, No. 651, issued in 2015, p. 311-316

  However, in the prior art, the method of mapping the deflection at the bottom dead center of the mold obtained by static analysis like the former to the rigid shell model cannot take into account changes in the deflection during molding, so sufficient analysis Accuracy cannot be obtained. In general, the structure of the mold is not determined in detail at the time of the die face design when the simulation is performed. Therefore, the method of modeling the entire mold as a solid element as in the latter is performed in a normal design routine. It is difficult to implement. Furthermore, the former method of mapping the static analysis results requires a large number of man-hours because the calculation needs to be performed multiple times, and the analysis with the latter solid model is much more difficult than the analysis with the normal shell model. Man-hours and calculation time are required.

  Accordingly, the present invention has been made in view of the above-described circumstances regarding press forming analysis, and is capable of performing highly accurate analysis while suppressing an increase in man-hours in a normal design routine. An object is to create a mold deflection model and perform molding analysis using this model.

  In order to solve the above-mentioned problems, a mold deflection model creation system and program according to the present invention are configured as follows.

One aspect of the mold deflection model creation system according to the present invention is:
A mold deflection model creation system in an analysis model of the mold for analyzing press molding using a press mold by a finite element method,
Among the molds, a fine mesh surface shell model acquisition unit that acquires a fine mesh surface shell model composed of a non-rigid shell element with a fine mesh as a model of a deflection-considering mold that needs to consider deflection, and
A coarse mesh solid model creating unit for creating a coarse mesh solid model composed of a solid element of an elastic body with a coarse mesh as the deflection considering mold;
It has an adhesion surface creation part which joins the surface of the rough mesh solid model, and the fine mesh surface shell model by predetermined contact conditions.

According to this aspect, the fine mesh surface shell model acquisition unit acquires a fine mesh surface shell model made of a non-rigid shell element made of a fine mesh as a model of the surface of the deflection-considering mold. The fine mesh surface shell model may be obtained using a fine mesh rigid shell model prepared in advance, or may be obtained by creating from CAD data.
The coarse mesh solid model creation unit creates a coarse mesh solid model obtained by modeling a deflection-considering mold with a solid element of a coarse mesh elastic body. The coarse mesh solid model may be created from CAD data, or may be simply created based on the size information of the deflection-considering mold.
The bonding surface creation unit joins the surface of the coarse mesh solid model and the fine mesh surface shell model under a predetermined contact condition. As the predetermined contact condition, for example, when a deflection-considering die is deformed, the surface of the coarse mesh solid model and the fine mesh surface shell model are in contact with each other and are in contact with each other. The condition is to keep a certain distance.
As described above, according to this aspect, the deflection-considering mold is created as a model in which the elastic non-rigid fine mesh surface shell model and the elastic coarse mesh solid model are combined, so the rigid shell model It is possible to perform sequential calculation of the deflection amount of the deflection-considering mold in the course of molding, which could not be performed by the mapping method. In addition, since the coarse mesh solid model greatly reduces the number of solid elements due to the coarse mesh, an increase in man-hours and calculation time can be suppressed.

  Next, in another aspect of the mold deflection model creation system according to the present invention, the coarse mesh solid model creation unit creates a coarse mesh surface shell model obtained by roughening a mesh of the fine mesh surface shell model, and at least the The simplified rough mesh solid model is created from the rough mesh surface shell model based on the size information of the deflection-considering mold.

  According to this aspect, since the shape of the coarse mesh solid model is simplified, the man-hour for creating the coarse mesh solid model and the calculation time of the deflection amount can be reduced.

  Next, in another aspect of the mold deflection model creation system according to the present invention, the coarse mesh solid model creation unit is configured so that the coarse mesh of the actual shape mold is based on shape data of the actual shape of the deflection-considering mold. It is characterized by creating a solid model.

  According to this aspect, the deflection mechanism can be reproduced more accurately than in the case of using a simple coarse mesh solid model.

Next, another aspect of the mold deflection model creation system according to the present invention is as follows.
The press molding die is a drawing press molding die including at least a die, a punch, and a blank holder,
The deflection considering mold is at least one of a die, a punch, and a blank holder.
It is characterized by that.

  According to this aspect, the deflection mechanism can be accurately reproduced while considering the balance of the cushion pin position with respect to the blank holder and the bead force balance of the wrinkle holding surface.

Next, one aspect of the mold deflection model creation program according to the present invention is as follows.
A mold deflection model creation program in an analysis model of the mold for analyzing press molding using a press mold by a finite element method,
A fine mesh surface shell model acquisition unit for acquiring a fine mesh surface shell model composed of a non-rigid shell element with a fine mesh as a model of the surface of the die that needs to consider deflection among the dies. ,
Coarse mesh solid model creation unit for creating a coarse mesh solid model composed of elastic solid elements with a coarse mesh for the deflection considering mold,
The surface of the coarse mesh solid model and the fine mesh surface shell model are functioned as an adhesive surface creation unit that joins the surfaces of the coarse mesh solid model with a predetermined contact condition.

  By causing the computer to execute the program according to this aspect, the above-described mold deflection model creation system can be implemented.

  According to the present invention, in a normal design routine, a mold deflection model capable of performing a highly accurate analysis while suppressing an increase in man-hours is created, and a molding analysis is performed using this model. Is possible.

1 is a block diagram showing an overall configuration of a mold deflection model creation system. It is a block diagram which shows the structure of the processing apparatus of the system. FIG. 2 is a block diagram illustrating a configuration of the storage device in FIG. 1. It is a block diagram which shows the structure of the program storage part of the storage device. It is a block diagram which shows the structure of the data storage part of the storage device. (A) is a figure which shows the data structure of the outline data table of blank material information data, (b) is a figure which shows the data structure of the stress-strain characteristic data table of blank material information data, (c) is blank material information data The figure which shows the data structure of a bending rigidity data table, (d) is a figure which shows the data structure of the bending plate thickness data table of blank material information data. (A) is a figure which shows the data structure of the data showing the number of the mold parts of a bending consideration mold information data, (b) is a figure which shows the data structure of the physical property data size information data of a deflection consideration mold information data. is there. (A) is a figure which shows the data structure of pin information data, (b) is a figure which shows the data structure of pin physical property. It is a figure which shows the data structure of the integration point data table of FEM analysis data. (A) is a figure which shows the data structure of the element structure table of FEM analysis data, (b) is a figure which shows the data structure of the material attribute data table of FEM analysis data, (c) is the data of the node coordinate table of FEM analysis data It is a figure which shows a structure. It is a figure which shows the example of the screen output-displayed on the output device of FIG. (A) is a figure which shows the state which the punch fell most with respect to the holder in the shaping | molding process of drawing press molding, (b) is the die face around the cavity of die | dye in the shaping | molding process of drawing press molding. The figure which shows the state which clamps between a surface and a wrinkle pressing surface of a holder with predetermined | prescribed cushioning force, and performs a wrinkle pressing, (c) raises a punch in the shaping | molding process of a drawing press molding, and blank material is made into the cavity of die | dye It is a figure which shows the state which pushes in and pinches | interposes the center part of a blank material between die | dye and a punch. (A) is a figure which shows the external shape of a blank material, (b) is a figure which shows a molded article, (c) is a figure which shows a product. It is a flowchart which shows the whole flow of a drawing press molding analysis method. It is a flowchart of a subroutine for mold deflection model creation when actual shape data of a deflection-considering mold cannot be prepared. It is a flowchart of a subroutine for mold deflection model creation when actual shape data of a deflection-considering mold can be prepared. It is a disassembled perspective view which shows the analysis model of a drawing press molding die. It is a figure for demonstrating the method of producing the rough mesh solid model SM2 of the holder H from the surface shell model SM1 of a rough mesh. It is a figure which shows the elastic body solid model of the fine mesh in a comparative example. (A) is a figure which shows a rough mesh solid model, (b) is a figure which shows a metal mold | die deflection model. (A) is a diagram showing a mold deflection model in which a surface of a coarse mesh solid model and a fine mesh surface shell model are combined under contact conditions, (b) is a diagram showing a fine mesh surface shell model, and (c) is a coarse mesh. It is a figure which shows a solid model. (A) is a diagram showing a mold deflection model in which a surface of a coarse mesh solid model and a fine mesh surface shell model are combined under a contact condition, (b) is a diagram showing a fine mesh surface shell model, and (c) is a diagram. It is a figure which shows a coarse mesh solid model. It is explanatory drawing explaining inflow of the raw material at the time of press molding. It is the graph which compared the inflow amount error of each raw material point in each analysis model. It is a graph which shows the mean square error of each analysis model. It is a top view which shows the point which measured the deflection amount of the holder in a different model. It is a graph which shows the deflection amount of the point 1 in FIG. It is a graph which shows the deflection amount of the point 2 in FIG. It is a graph which shows the deflection amount of the point 3 in FIG. It is a graph which shows the deflection amount of the point 4 in FIG. It is the graph which compared the analysis time in each analysis model. It is explanatory drawing explaining the subject of the conventional drawing press molding.

  A mold deflection model creation system and program according to an embodiment of the present invention will be described.

(1) Outline of Mold Deflection Model Creation System FIG. 1 is a diagram showing a configuration of a computer 10 that is the center of a mold deflection model creation system according to an embodiment of the present invention. As shown in FIG. 1, a computer 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, a printer, or the like. Output device 14.

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

  As shown in FIG. 2, the processing apparatus 11 includes a mold shape data acquisition unit 110, a mold shell element data acquisition unit 120, a deflection consideration mold information acquisition unit 130, a boundary condition acquisition unit 140, a mold, and the like. A deflection model creation unit 200, a molding analysis unit 400, and an analysis result display unit 500 are provided.

  The mold shape data acquisition unit 110 acquires mold shape data from the storage device 12. The mold shell element data acquisition unit 120 acquires mold shell element data from the storage device 12. The deflection considering mold information acquisition unit 130 acquires information on a mold as a deflection considering mold described later. The boundary condition acquisition unit 140 acquires a boundary condition including pin information data. The mold deflection model creation unit 200 creates a mold deflection model. The forming analysis unit 400 performs drawing press forming analysis using a mold deflection model. The analysis result display unit 500 displays the analysis result obtained by the molding analysis unit 400.

  As shown in FIG. 2, the mold deflection model creation unit 200 includes a fine mesh surface shell model acquisition unit 210, a coarse mesh solid model creation unit 220, and an adhesive surface creation unit 230.

  The mold is composed of a mold part such as a die, a holder, and a punch, and members such as a cushion pin and a guide, but the deflection-considering mold needs to consider deflection among the mold parts. It is a mold. All of the die, the holder, the punch, and the like may be used as a bending-considering die, or a die part as a bending-considering die may be selected depending on the situation. In the present embodiment, an example in which the holder is a bending-considering mold will be described as an example.

  The fine mesh surface shell model acquisition unit 210 acquires a non-rigid fine mesh surface shell model from the die shell element data of the deflection-considering die. In the present embodiment, as an example, a fine mesh surface shell model is acquired from mold shell element data. The bonding surface creation unit 240 combines the surface of the coarse mesh solid model and the fine mesh surface shell model according to the contact condition.

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

FIG. 4 is a block diagram schematically showing the configuration of the program storage unit 12A of FIG. As shown in FIG. 4, the program storage unit 12A includes a mold shape data acquisition program PR1, a mold shell element data acquisition program PR2, a deflection consideration mold information acquisition program PR3, a boundary condition acquisition program PR4, and a mold deflection model creation. Program storage units 12A _{1 to} 12A ₇ each storing a program PR5, a molding analysis program PR6, and an analysis result display program PR7 are provided. The programs PR1, PR2, PR5 to PR7 are a mold shape data acquisition unit 110, a mold shell element data acquisition unit 120, a mold deflection model creation unit 200, a molding analysis unit 400, and an analysis result display unit in the processing apparatus 11 described above. 500 respectively. Further, the program PR3 is executed by the deflection consideration mold information acquisition unit 130 in the processing apparatus 11 described above, and the program PR4 is executed by the boundary condition acquisition unit 140.

FIG. 5 is a block diagram schematically showing the configuration of the data storage unit 12B of FIG. As shown in FIG. 5, the data storage unit 12B includes mold shape data DT1, blank material information data DT2, mold shell element data DT3, deflection consideration mold information data DT4, pin information data DT5, molding condition data DT6, And data storage units 12B _{1 to} 12B ₇ for storing the FEM analysis data DT7, respectively.

  Here, FIGS. 6 to 10 are diagrams showing the data structure of the above-described data DT1 to DT7. The data DT1 to DT7 stored in the data storage unit 12B will be described in detail with reference to FIGS.

(1-2-1) Mold Shape Data Mold shape data DT1 is, for example, CAD data designed with an existing CAD system, STL (Standard It consists of existing mold shape data obtained by various methods such as (Triangulated Language) data.

(1-2-2) Blank Material Information Data Blank material information data DT2 is various data related to a blank material that is a material to be press-formed. Specifically, as shown in FIGS. 6 (a) to 6 (d), an outline data table, a stress strain characteristic data table, a bending stiffness data regarding the XY coordinates of a plurality of nodes constituting the outline of the blank material. And attributes such as plate thickness data. The blank material information data DT2 is input to the processing device 11 via the input device 13 such as a liquid crystal display or a keyboard.

(1-2-3) Mold Shell Element Data Specifically, the mold shell element data DT3 includes shell element data such as a die, a holder, a punch, a pad, and a bending blade depending on the molding method. For example, in the case of drawing, holder shell element data and die shell element data regarding the die face surface of the blank holder, and punch shell element data regarding punching are included. In the present embodiment, as an example, the case of drawing will be described.

(1-2-4) Deflection Considering Mold Information Data Deflection considering mold information data DT4 is data relating to the shape, size, and material characteristics of the deflection considering mold. In the present embodiment, as an example, a case of analyzing the deflection of a blank holder that is one of the deflection-considering molds will be described. As shown in FIG. 7, the deflection-considering mold information data DT4 includes the number of parts of the deflection-considering mold, an elastic solid modeling flag, physical property data, and solid model size data. When the flag for elastic solid modeling is 0, the mold part remains a rigid shell, and when the flag is 1, the mold part is created as an elastic solid model. Physical property data is composed of Young's modulus and Poisson's ratio.

(1-2-5) Pin information data The pin information data DT5 is data relating to the cushion pin that supports the blank holder. Specifically, as shown in FIG. 8, the pin number of each cushion pin, the base end position coordinates regarding the position of the base end, the data such as the diameter, and the physical properties of the pin (for example, Young's modulus (longitudinal elastic modulus), Poisson's ratio) and other data.

(1-2-6) Molding condition data The molding condition data DT6 includes parameters such as a holder cushioning force (wrinkle pressing force) and a pad load, which are molding conditions during drawing press molding.

(1-2-7) FEM Analysis Data Finally, the FEM analysis data DT7 that is numerically analyzed by the finite element method in the molding analysis unit 400 will be described. The FEM analysis data DT7 includes an integration point data table, an element configuration table, a material attribute data table, and a nodal coordinate table. Hereinafter, each table will be described with reference to FIGS. 9 and 10.

As shown in FIG. 9, the integration point data table includes integration point numbers P1, P2,... Included in each shell element (hereinafter, simply referred to as “element”) constituting the shape model of a molded product that is drawn by press molding. Element numbers E1, E2,... That include each integration point, position components (X, Y, Z) in the element coordinate system of each integration point, and stress components (σ _XX , σ _XY , σ _XZ , σ _YX , σ _{YY, σ YZ, σ ZX,} σ ZY, and sigma _ZZ), is constructed from strain components _{(ε XX, ε XY, ε} XZ, ε YX, ε YY, ε YZ, ε ZX, ε ZY, ε ZZ) and ing.

  As shown in FIG. 10A, the element configuration table includes element numbers E1, E2,..., Material numbers M of each element, in-plane integration points and out-of-plane integration points, first node numbers included in each element, It consists of a second node number, a third node number, and a fourth node number N.

  As shown in FIG. 10B, the material attribute data table is composed of material numbers M ... and material data.

  As shown in FIG. 10C, the node coordinate table is composed of node numbers N1, N2,..., And position components (X, Y, Z) in the entire coordinate system of each node.

(1-3) Input Device The input device 13 is used for inputting various data described above, setting various analysis conditions such as a set value of cushion force, or controlling the system.

(1-4) Output device The output device 14 displays an input setting screen, analysis results such as plate thickness distribution and strain distribution, and the like. For example, as shown in FIG. 11, the output device 14 displays a three-dimensional graphic display of a drawn press-formed product indicating the result of the molding analysis.

(2) Drawing Press Molding Device A drawing press molding process for drawing press molding for analysis by the above-described drawing press molding analysis system will be described with reference to FIGS.

  FIG. 12 is an explanatory diagram for explaining a forming process of drawing press forming. The punch P is disposed with a gap with respect to the inner wall surface of the opening of the holder H so that the punch P can be moved up and down inside the opening of the holder H. As shown in FIG. 12A, in the state where the punch P is lowered most with respect to the holder H, the lowermost end of the punch P becomes the same height or lower than the upper surface around the opening of the holder H.

  In the press molding using this press molding apparatus, first, as shown in FIG. 12 (b), the die face surface around the cavity C of the die D and the holder are placed around the flat blank B as the material of the product. Wrinkle pressing is performed with a predetermined cushioning force between the H wrinkle pressing surface. At this time, the ridge Hb of the holder H pushes the blank material B into the concave groove Db of the opposing die D, thereby forming a bead b (see FIG. 13B) on the blank material B.

  Next, as shown in FIG. 12C, the punch P is raised, the blank material B is pushed into the cavity C of the die D, and the central portion of the blank material B is sandwiched between the die D and the punch P. Press.

  In this drawing press forming, the die D and the holder H may be moved up and down with the punch P fixed. In the press mold, the lower die may be constituted by the die D, and the upper die may be constituted by the punch P and the blank holder H. Furthermore, the press molding may be either a cold press or a hot press.

  FIG. 13 is an explanatory diagram for explaining a manufacturing process of a molded product. According to the press molding process shown in FIG. 12 as described above, a molded product as shown in FIG. 13 (b) can be formed from a flat blank B having an outer shape as shown in FIG. 13 (a). it can. This molded product is composed of a product surface portion S and a wrinkle holding surface portion around the product surface portion S, and the product surface portion S is mainly molded in the cavity C between the punch P and the die D of the above-described molding apparatus, The wrinkle holding surface portion is formed between the blank holder H and the die D. Further, a bead b is formed between the concave groove Db of the die D and the ridge Hb of the blank holder H on the wrinkle holding surface portion.

  When this molded product is punched along the product shape outline Ls that is the outline of the product surface portion S, a product as shown in FIG. 13C can be obtained.

(3) Drawing press molding analysis method using mold deflection model creation system Drawing press molding analysis method using mold deflection model creation system will be described below.

(3-1) Overall Flow of Drawing Press Molding Analysis Method FIG. 14 is a flowchart showing the overall flow of the drawing press molding analysis method of the present embodiment. The overall flow of the drawing press forming analysis method will be described in accordance with the processing routine of the main routine shown in the flowchart of FIG.

  First, the mold shell element data acquisition unit 120 acquires the mold shell element data DT3 from the data storage unit 12B (step S1). The mold shell element data acquisition unit 120 acquires a standard molding analysis model, which includes rigid mold shell element data. The die shell element data is a rigid shell model made of a fine mesh. In this embodiment, the die D rigid shell model, the punch P rigid shell model, and the holder H rigid shell model are the die shell elements. Data is stored in the data storage unit 12B.

  Next, the deflection considering mold information acquisition unit 130 acquires the deflection considering mold information data DT4 from the data storage unit 12B (step S2). When the deflection considering mold is the holder H, the deflection considering mold information includes at least the size information of the holder H, that is, the horizontal size and the vertical size of the holder H.

  Next, the boundary condition acquisition unit 140 acquires a boundary condition including the pin information data DT5 from the data storage unit 12B (step S3). When a guide or the like is in contact with the holder H, information such as a guide is also used as a boundary condition.

  Next, the fine mesh surface shell model acquired from the mold shell element data is combined with the coarse mesh solid model acquired based on the deflection consideration mold information data DT4 or the actual shape data by the mold deflection model creation unit 200. Then, a mold deflection model is created (step S5).

  Finally, the forming analysis unit 200 performs a drawing press forming analysis based on the forming condition data DT6, the blank material information data DT2, and the like (step S6).

  As described above, the drawing press forming analysis can be performed.

(3-2) Mold Deflection Model Creation Method Next, mold deflection model creation (step S5), which is a subroutine of the above-described flowchart, will be described with reference to FIGS. 15 and 16 are both flowcharts of a subroutine of the mold deflection model creation process (step S5) shown in FIG. FIG. 15 shows the case where the actual shape data of the deflection-considering mold is not prepared, and FIG. 16 shows the case where the actual shape data of the deflection-considering mold is prepared.

First, with reference to FIG. 15, a description will be given of a mold deflection model creation process in the case where actual shape data of a deflection-considering mold is not prepared.
First, the fine mesh surface shell model acquisition unit 210 acquires a non-rigid fine mesh surface shell model from the mold shell element data DT3 on the holder surface acquired by the mold shell element data acquisition unit 120 (step S11). ). The die shell element data DT3 on the holder surface is a fine mesh rigid shell model, but the fine mesh surface shell model acquisition unit 210 performs an elastic solid modeling with a flexure-considering die DT4 from the rigid shell model. A fine mesh surface shell model is obtained by setting the specified mold (holder) to be non-rigid.

  Next, the coarse mesh solid model creation unit 220 creates a coarse mesh surface shell model by roughening the mesh of the fine mesh surface shell model (step S12). The rough mesh surface shell model may be created by using the CAD data on the holder surface among the CAD data included in the mold shape data DT1.

  Next, the coarse mesh solid model creation unit 220 uses a rough mesh solid surface shell mesh created based on the solid model size of the deflection consideration mold information data DT4 from the rough mesh surface shell model to generate a coarse mesh. A coarse mesh solid model of an elastic body is simply created (step S13).

  Next, the surface of the coarse mesh solid model and the fine mesh surface shell model are combined under the contact condition by the adhesive surface creation unit 240 (step S14). The contact condition is used for contact calculation. As a contact condition, for example, when the mold deflection model is deformed, the surface of the coarse mesh solid model and the fine mesh surface shell model are in contact with each other, and the portions that are not in contact with each other A condition such as maintaining a certain distance can be mentioned.

  When the actual shape data of the deflection considering mold is not prepared, the mold deflection model is created as described above.

Next, with reference to FIG. 18, a description will be given of a mold deflection model creation process when actual shape data of a deflection-considering mold is prepared.
First, the coarse mesh solid model creation unit 220 uses the CAD data of the actual shape of the holder H as the mold structure opposite to the die D among the CAD data included in the mold shape data DT1, and uses the coarse mesh solid model creation unit 220 to generate a coarse mesh. A coarse mesh solid model of an elastic body made of solid elements is created (step S21).

  Next, the fine mesh surface shell model acquisition unit 210 acquires a non-rigid fine mesh surface shell model from the mold shell element data DT3 on the holder surface acquired by the mold shell element data acquisition unit 120 (step S22). ). This process is the same as the process of step S11 of FIG.

  Next, the surface of the coarse mesh solid model and the fine mesh surface shell model of the fine mesh are combined under the contact condition by the adhesive surface creation unit 240 (step S24). The contact condition is used for contact calculation. This process is the same as the process of step S14 in FIG.

  Next, a specific example of the mold deflection model creation process in the case where the actual shape data of the above-described deflection consideration mold cannot be prepared will be described with reference to FIGS. FIG. 17 is an exploded perspective view showing an analysis model of a drawing press mold. FIG. 18 is a diagram for explaining a method of creating a coarse mesh solid model SM2 of the holder H from the coarse shell surface shell model SM1. FIG. 19 is a diagram showing an elastic solid model of a fine mesh in a comparative example. FIG. 20 is a diagram showing the coarse mesh solid model SM2 of the present embodiment and the mold deflection model TM of the present embodiment. FIG. 21 is a diagram illustrating an example of a mold deflection model according to the present embodiment. FIG. 22 is a diagram showing an example of the mold deflection model TM of the present embodiment.

  The model DM of the die D and the model PM of the punch P shown in FIG. 17 are created as a rigid shell model made of a fine mesh. In the example described here, deflection is not considered for these models.

  The fine mesh surface shell model EM on the surface of the holder is a fine mesh surface shell model on the surface of the holder H, and is composed of fine mesh non-rigid shell elements.

  The coarse mesh surface shell model SM1 is a surface shell model obtained by roughening the mesh of the fine mesh surface shell model EM on the surface of the holder H. The coarse mesh surface shell model SM1 is composed of solid elements of an elastic body. A coarse mesh solid model SM2 of the holder H is created.

  As indicated by an arrow J in FIG. 17, the fine mesh surface shell model EM on the holder surface and the surface of the coarse mesh solid model SM2 are coupled according to contact conditions. A pin Hp, a guide G, and the like provided around the holder H are defined as boundary conditions of the coarse mesh solid model SM2. As indicated by an arrow K, the pin Hp is coupled to the bottom surface of the coarse mesh solid model SM2.

  As described above, the non-rigid shell model EM and the coarse mesh solid model SM2 are the same as each other by connecting the fine mesh surface shell model EM and the surface of the coarse mesh solid model SM2 according to contact conditions. It keeps a certain distance where it does not touch. Then, by defining and analyzing the coarse mesh solid model SM2 as an elastic body, the deflection distribution of the surface of the coarse mesh solid model SM2 and the deflection distribution of the fine mesh surface shell model EM become equivalent.

  When creating the coarse mesh solid model SM2, first, a fine mesh surface shell model EM is acquired. Next, a rough mesh surface shell model SM1 is created by roughening the fine mesh surface shell model EM. The coarse mesh surface shell model SM1 is located at the same coordinates as the fine mesh surface shell model EM. Then, an extended surface of the coarse mesh surface shell model SM1 is created based on the sizes of the holder H in the X, Y, and Z directions, and a coarse mesh solid model SM2 of the holder H is created based thereon. Specifically, a rough mesh is created by creating a surface obtained by extending the outer circumference of the surface shell model of the coarse mesh to a rectangular size of Ximn, Xmax, Ymin, Ymax in the horizontal direction of the solid model of the mold. In addition, a rough mesh is automatically created on the vertical wall surface where the outer circumference of the created extension surface and the inner circumference of the holder are each extended to the vertical size Zmin and on the bottom surface where the Zmin position is created. . All of the above surface shell elements are used to create a solid model mesh with a coarse mesh.

  As for the size in the Z direction, when the lower holder H is a deflection-considering die as shown in FIG. 19, only the size in the −Z direction is sufficient. However, when the upper mold part is a deflection-considering mold, the size in the + Z direction is used.

  When a rectangular mold part such as a pad is a deflection-considering mold, only the size in the Z direction may be defined. Alternatively, the surface data of the deflection-considering mold may be directly prepared without using the size in the XY direction and the size in the Z direction.

  If the actual shape data of the deflection-considering mold is not prepared, the simplified coarse mesh solid model SM2 is created in this way.

  As shown in FIG. 19, it takes a lot of calculation time to perform molding analysis using the elastic solid model UM consisting of a fine mesh for the holder H as a deflection-considering die. I can't do it.

Therefore, in the present embodiment, as shown in FIG. 20A, the holder H is modeled with a coarse mesh solid model SM2 made of a solid element made of an elastic body with a coarse mesh. Only the surface of the holder H required for contact calculation is a fine mesh surface shell model EM of a fine mesh elastic body, and as shown in FIG. 20 (b), the surface of the coarse mesh solid model SM2 and the fineness of the elastic body are fine. A simple mold deflection model TM is created by combining the mesh surface shell model EM with contact conditions.
When creating a solid model using an actual shape, preparation of 3D mold structure data is required. However, generally, since the mold structure is not fixed at the time of die face design, it is difficult to prepare such detailed 3D mold structure data. Therefore, when it is difficult to prepare detailed 3D mold structure data, a simple mold deflection model TM is created. By creating a simple mold deflection model TM, an increase in calculation time can be suppressed.

  FIG. 21 and FIG. 22 also show examples of the simplified mold deflection model TM of the present embodiment. FIG. 21 (a) shows a simple mold deflection model TM in which the surface of the coarse mesh solid model SM2 and the fine mesh surface shell model EM are combined under contact conditions, and FIG. 21 (b) shows the fine mesh surface shell. A model EM is shown, and FIG. 21C shows a coarse mesh solid model SM2.

  FIG. 22 (a) shows a simple mold deflection model TM in which the surface of the coarse mesh solid model SM2 and the fine mesh surface shell model EM are combined under contact conditions, and FIG. 22 (b) shows the fine mesh surface shell. A model EM is shown, and FIG. 22C shows a coarse mesh solid model SM2.

  On the other hand, although illustration of a specific example of the mold deflection model creation process in the case where the actual shape data of the deflection-considering mold has been prepared is omitted, first, based on the actual shape data, the elastic body is formed with a coarse mesh. Create a coarse mesh solid model consisting of solid elements. Next, a non-rigid fine mesh surface shell model is obtained. Then, the fine mesh surface shell model and the surface of the coarse mesh solid model are coupled by contact conditions.

  In the present embodiment, as an example, a case has been described in which the holder H is a bending-considering mold among the mold parts, but the present invention is not limited to such an embodiment. For example, a die D, punch P, pad, or the like that is a mold part may be used as a bending-considering mold.

  Moreover, although this embodiment demonstrated the case of drawing (drawing) as an example of press molding, this invention is not limited to such an aspect. The present invention is also applicable to foam molding. In this case, a die part, a punch, and a pad that are mold parts may be appropriately used as a mold considering deflection. Furthermore, the present invention can also be applied to bending molding. In this case, the punch, pad, and bending blade, which are mold parts, may be used as a mold considering deflection.

  In press molding, a press machine including an upper mold ram attached above the die and a bolster attached below the punch is used. Such a press machine mold ram and bolster may be modeled in the same manner as a deflection-considering mold.

  As described above, in the present embodiment, the rough mesh solid model SM2 is created using the mold part such as the holder H as a deflection-considering mold, and the surface of the coarse mesh solid model SM2 and the fine mesh surface shell model EM are contacted. The model was modeled with a mold deflection model TM coupled with the above. As a result, by analyzing the deformation of the mold deflection model TM, it is possible to perform a molding analysis that sequentially considers the amount of deflection during molding of the holder H.

  In addition, according to the present embodiment, the mold deflection model TM combines the coarse mesh solid model SM2 made of a coarse mesh solid element and the fine mesh surface shell model EM made of a fine mesh shell element. The amount of deflection may be calculated for the coarse mesh solid model SM2 having a coarse mesh. Therefore, it is possible to suppress an increase in man-hours for data preparation and calculation time.

(4) Effect of mold deflection model creation system Assuming that the elastic solid model consisting of all fine meshes is closest to the actual machine, the inflow volume error between this fine mesh elastic solid model and other models The effects were compared in terms of deflection amount and calculation time. Hereinafter, this effect comparison will be described with reference to FIGS.

(4-1) Inflow error FIG. 23 shows an analysis model after the blank material B is press-molded with a predetermined wrinkle pressing force. In addition, P1 to P8 in the peripheral part of the blank material B have shown the measurement points of the inflow amount arrange | positioned at the substantially equal intervals of the number from which sufficient sample number is obtained.

  As shown in FIG. 23, the blank material B of the present embodiment flows from the + Y direction and the −Y direction toward the center in any of P1 to P8.

The model used for the comparison is as follows.
Case 0: fine mesh elastic solid model Case 1: fine mesh rigid shell model Case 2: fine mesh non-rigid shell model + coarse mesh solid elastic solid model Case 3: fine mesh non-rigid shell model + coarse mesh Simplified elastic solid model Case 4: Rigid shell model mapping bottom dead center deflection (conventional method)

  The shape of the elastic solid model of the fine mesh of Case 0 and the actual shape of the solid solid model of the coarse mesh of Case 2 are the same as the actual shape of the holder H, and a simple elastic solid of the coarse mesh of Case 3 The model has a simple shape as shown in FIG. 17, for example.

  FIG. 24 is a graph comparing the inflow amount errors at the points P1 to P8 of the blank B when the forming analysis is performed using each model of Case 0 to Case 4. FIG. 24 is a graph showing the mean square error of the inflow amount of each model from Case 1 to Case 4 with respect to the Case 0 model.

  As shown in FIG. 24, based on the case 0 fine mesh elastic solid model, the case 1 fine mesh rigid shell model and the case 4 rigid shell model in which the deflection of the bottom dead center of Case 4 is mapped are inflow errors. It can be seen that is large. Since the Case 1 model and the Case 4 model are models that cannot take into account the sequential change of the deflection amount, it can be seen from these results that the deflection amount of the mold affects the calculation accuracy of the inflow amount.

  On the other hand, a model in which a non-rigid shell model of a fine mesh of Case 2 and a solid elastic model of a coarse mesh are combined, and a non-rigid shell model of a fine mesh in Case 3 and a simple elastic body of a coarse mesh In the model combined with the solid model, the error of the inflow amount is greatly reduced. Since the Case2 model and the Case3 model are models that can take into account the sequential change of the deflection amount, it is understood that the inflow amount can be calculated with high accuracy.

  FIG. 25 is a graph showing the mean square error of each model. Further, as shown in FIG. 25, when the elastic solid model of the fine mesh of Case 0 is used as a reference, the mean square error of the rigid shell model of the fine mesh of Case 1 is 0.78 mm, and the deflection of the bottom dead center of Case 4 is mapped. The mean square error of the rigid shell model was 0.65 mm.

  On the other hand, the mean square error of the model obtained by combining the non-rigid shell model of the fine mesh of Case 2 and the elastic solid model of the actual shape of the coarse mesh is 0.25 mm. The mean square error of the model obtained by combining the simple elastic solid model of the mesh was 0.15 mm.

  Therefore, the analysis model of the above Case 2 and Case 3 of the present invention agrees well with the elastic solid model of fine mesh in terms of inflow compared to the rigid shell model in which the deflection of the bottom dead center of Case 1 and Case 4 is mapped. In other words, it was found that an analysis result closer to the inflow amount when actually molded is obtained.

(4-2) Deflection amount The deflection amount of the holder H when the molding analysis was performed with the respective analysis models of the present invention was compared. FIG. 26 is a plan view showing points at which the deflection amount of the holder H is measured in each model. 26 to 30 are graphs showing the amount of deflection at each point. Since the deflection amounts of the Case 2 and Case 3 models are substantially the same, in FIGS. 26 to 30, the deflection amounts of these models are indicated by one broken line.

  As shown in FIGS. 26 to 30, the analysis model of Case 2 and Case 3 of the present invention has a deflection amount close to that of the elastic solid model of the fine mesh of Case 0 at any point. Therefore, the analysis model of Case 2 and Case 3 of the present invention well reproduces the tendency of deflection of the elastic solid model of Case 0 fine mesh. Since Case 1 is a rigid body, the deflection is zero and it is not displayed in the graphs of FIGS.

(4-3) Analysis Time FIG. 31 is a graph comparing the analysis times of the above analysis models. As shown in FIG. 31, the elastic solid model of the fine mesh of Case 0 is 22.52 minutes, whereas the rigid solid model of Case 1 is 11.33 minutes, and the analysis model of Case 2 of the present invention is 11.82 minutes. The analysis model of Case 3 of the present invention was 11.75 minutes. Thus, the analysis time of the analysis model of Case 2 and Case 3 of the present invention is approximately half the analysis time of the elastic solid model of the fine mesh of Case 0, and is almost the same as the analysis time of the rigid shell of Case 1.

  From the above, according to the mold deflection model creation system of the present embodiment, the analysis time is substantially shorter than the analysis time of the fine mesh elastic solid model, and is equivalent to the analysis result of the fine mesh elastic solid model. It has been found that an analysis result having a higher accuracy, that is, an analysis result closer to the actual molding result than before can be obtained.

  The models of Case 2 and Case 3 described above are models in which a fine mesh elastic shell model and a coarse mesh elastic solid model are combined. The difference between these models is that the shape of the Case2 model is the same as the actual shape of the holder H, whereas the shape of the Case3 model is based on the surface shape data of the holder H as described above. This is in a simple shape created by a program based on the size information of the holder H. Since the Case2 model has a real shape, the deflection can be reproduced with higher accuracy. However, if it is a simple shape like the Case3 model, the man-hours and calculation time for data preparation can be reduced. Can be shortened.

(5) Features of Mold Deflection Model Creation System According to the mold deflection model creation system of this embodiment, the holder H is modeled by a coarse mesh solid model made of an elastic solid element with a coarse mesh, and the surface of the holder H Is modeled by a fine mesh surface shell model consisting of fine mesh and non-rigid shell elements. Further, the surface of the coarse mesh solid model and the fine mesh surface shell model are combined under contact conditions to create a mold deflection model.
This is because it takes a lot of calculation time to perform molding analysis using a solid model consisting entirely of a fine mesh, and cannot be adopted in practice.
By combining the surface of the coarse mesh solid model and the fine mesh surface shell model according to the contact conditions to create a mold deflection model, the deflection mechanism of the deflection-considering mold is shortened while shortening the preparation man-hours and calculation time. Can be reproduced.

  In addition, according to the mold deflection model creation system of the present embodiment, it is possible to perform molding analysis that sequentially considers the amount of deflection during molding of the holder H by solving the deformation of the mold deflection model TM.

  Furthermore, according to the mold deflection model creation system of the present embodiment, the mold deflection model is a combination of a coarse mesh solid model made up of coarse mesh solid elements and a fine mesh surface shell model made up of fine mesh mesh elements. Therefore, the calculation of the deflection amount during the molding may be performed on the coarse mesh solid model of the coarse mesh. Therefore, an increase in calculation time can be suppressed.

[Modification]
The present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

  In the above-described embodiment, the mold analysis model generation unit 100 and the molding analysis unit 400 are both provided in the processing apparatus 11. However, only the molding analysis unit 400 is provided in another processing apparatus, and the processing apparatus 11 includes The mold analysis model generated by the provided mold analysis model generation unit 100 may be transferred to another processing apparatus in which the molding analysis unit 400 is provided.

  Furthermore, in the above-described embodiment, an example of creating a mold deflection model in a drawing press mold has been described, but a mold deflection model in a bending press mold may be created. In this case, for example, a punch, a pad, a die, and a bending blade may be used as a die considering bending.

  As described above, according to the present invention, it is possible to create a mold deflection model capable of performing highly accurate analysis while suppressing an increase in man-hours in a normal design routine. There is a possibility that the present invention is suitably used in the field of manufacturing panel parts for vehicle body construction.

110: Mold shape data acquisition unit 120: Mold shell element data acquisition unit 130: Deflection-considering mold information acquisition unit 150: Pin information acquisition unit 200: Mold deflection model creation unit 210: Fine mesh surface shell model acquisition unit 220 : Coarse mesh solid model creation unit 230: Bonded surface creation unit

Claims (5)

A mold deflection model creation system in an analysis model of the mold for analyzing press molding using a press mold by a finite element method,
Among the molds, a fine mesh surface shell model acquisition unit that acquires a fine mesh surface shell model composed of a non-rigid shell element with a fine mesh as a model of a deflection-considering mold that needs to consider deflection, and
A coarse mesh solid model creating unit for creating a coarse mesh solid model composed of a solid element of an elastic body with a coarse mesh as the deflection considering mold;
An adhesive surface creation unit that couples the surface of the coarse mesh solid model and the fine mesh surface shell model under a predetermined contact condition;
Mold deflection model creation system characterized by that. The coarse mesh solid model creation unit creates a coarse mesh surface shell model obtained by roughening the mesh of the fine mesh surface shell model, and based on the coarse mesh surface shell model based on at least size information of the deflection-considering mold, Create a simple rough mesh solid model,
The mold deflection model creation system according to claim 1, wherein: The coarse mesh solid model creation unit creates the coarse mesh solid model of the actual shape type based on the shape data of the actual shape of the deflection-considering mold,
The mold deflection model creation system according to claim 1, wherein: The press molding die is a drawing press molding die including at least a die, a punch, and a blank holder,
The deflection considering mold is at least one of a die, a punch, and a blank holder.
The mold deflection model creation system according to any one of claims 1 to 3, wherein the mold deflection model creation system is provided. A mold deflection model creation program in an analysis model of the mold for analyzing press molding using a press mold by a finite element method,
A fine mesh surface shell model acquisition unit for acquiring a fine mesh surface shell model composed of a non-rigid shell element with a fine mesh as a model of the surface of the die that needs to consider deflection among the dies. ,
Coarse mesh solid model creation unit for creating a coarse mesh solid model composed of elastic solid elements with a coarse mesh for the deflection considering mold,
Causing the surface of the coarse mesh solid model and the fine mesh surface shell model to function as an adhesive surface creation unit that couples according to predetermined contact conditions;
A mold deflection model creation program characterized by that.