JP7541241B2 - Press forming simulation method - Google Patents

Description

The present invention relates to a press molding simulation method.

Conventionally, there has been a method of actually measuring local deformation of a press die in order to reflect the deformation expected in the press die during press forming in the design of the press die.
However, the conventional method was a method of actually measuring the local deformation of a specific press die when that specific press die was used, and was not a method that took into account the rigidity of the press machine when designing the press die.

JP 2011-145247 A

In view of the problems in the background art described above, the present invention aims to provide a press forming simulation method that can accurately reproduce press forming while reducing the calculation load.

The gist of the present invention is as follows:

(1) A press-molding simulation method according to one aspect of the present invention is a press-molding simulation method for predicting changes in physical quantities of a workpiece when the workpiece is pressed under a predetermined load by a press machine equipped with a press die to form a press-molded product, the method including a classification step of classifying the press machine into an elastic support portion that elastically supports the press die and a rigid support portion that rigidly supports the elastic support portion; an analytical model preparation step of preparing an analytical model in which the rigid support portion is modeled as a rigid body and the elastic support portion is modeled as an elastic body supported by the rigid support portion; and a calculation step of estimating a change in a physical quantity of a workpiece when the workpiece is pressed under a predetermined load by a press machine equipped with a press die. the discretized displacement model preparation step of preparing a discretized deflection model in which a discretized displacement distribution, which is a distribution, is expressed as a product of an initial linear spring constant distribution, which is a distribution of initial linear spring constants in each of the divided regions, and the load; a reference model preparation step of preparing a reference displacement distribution, which is a distribution of displacement in each of the divided regions, based on press forming simulation results using the analytical model or actual measurement results in a press forming test using the press; and a linear spring constant distribution calculation step of correcting the initial linear spring constant distribution based on a difference between the reference displacement distribution and the discretized displacement distribution, to calculate a linear spring constant distribution, which is a distribution of a finite number of linear spring constants.
(2) In the above (1), the elastic support portion may include a slide or a bolster that is in direct contact with the press die.
(3) In the above (1) or (2), the rigid support portion may include a crown.
(4) In any of (1) to (3) above, the method may include an elastic-plastic analysis process for performing an elastic-plastic analysis of a work model in which the work is modeled using a modified discretized deflection model expressed as the product of the linear spring constant distribution and the load, when the load is applied to the work model.

The present invention provides a press molding simulation method that can accurately reproduce press molding while reducing the calculation load.

FIG. 1 is an explanatory diagram of a press molding apparatus including a press machine and a press die. FIG. 1 is an explanatory diagram of an analysis model. 1A is a diagram illustrating a discrete deflection model in a plan view, and FIG. 1B is a diagram illustrating a discrete deflection model in a front view; FIG. 1 is a flow diagram of a press-molding simulation method. FIG. 13 is an explanatory diagram of an elastic support part model. FIG. 1 is a conceptual diagram of a linear spring constant distribution. FIG. 13 is a flow diagram of a linear spring constant distribution calculation process.

FIG. 1 is an explanatory diagram of a press molding apparatus 1 including a press machine 10 and a press die 20.
1, the press forming apparatus 1 is a machine that applies strong pressure to a workpiece W (e.g., a metal material, also called a blank) to be processed, and deforms the workpiece W into the shape of a press die to manufacture a press-formed product. In general, the press forming apparatus 1 includes a press machine 10 and a press die 20 attached to the press machine 10.

The press 10 includes a bolster 11 to which a lower die 21 is attached at the top, a slide 12 to which an upper die 22 is attached at the bottom, a drive unit 13 that drives the bolster 11 and the slide 12 to move closer to or farther apart, a crown 14 that supports the slide 12, and a bed 15 that supports the bolster 11.

The press die 20 includes a lower die 21 and an upper die 22.

The structure of the press machine 10 differs depending on the press capacity, specifications, design concept, etc. of the press machine 10. Even if the press capacity, specifications, design concept, etc. are the same, there are differences in the structure of the press machine 10 due to manufacturing errors, etc. Furthermore, the structure of the press die 20 attached to the press machine 10 differs depending on the specifications of the press-molded product to be manufactured. Therefore, even if the press load is the same, the rigidity of the press machine 10 differs due to differences in the structure of the press machine 10 and the structure of the press die 20, and the deformation state of the press machine 10 differs.

Incidentally, in order to manufacture a press-molded product with high accuracy by press molding, it may be necessary to estimate in advance the deflection ω (meaning the planar distribution of vertical displacement; hereinafter, sometimes referred to as displacement or deformation) of the press machine 10 for the shape of the press die 20, including the molding surface that contacts the workpiece W that is the workpiece of the press-molded product. In this case, it is preferable to grasp the rigidity of the press machine 10, which is the relationship between the load F (press load) and the deflection ω of the press machine 10.
However, in order to accurately measure the deflection ω of the press machine 10 in order to grasp the rigidity of the press machine 10, a large number of measurement points are required, which requires a corresponding cost for equipment, etc. Furthermore, even if the rigidity of the press machine 10 is calculated using FEM or the like, there may be a deviation from the actual rigidity, or the calculation load may be excessive.

Therefore, the present invention is a press molding simulation method for predicting a change in a physical quantity of a workpiece when a press machine equipped with a press die presses the workpiece with a predetermined load to form a press-formed product. The press molding simulation method of the present invention includes a classification step of classifying the press machine into an elastic support part that elastically supports the press die and a rigid support part that rigidly supports the elastic support part. The press molding simulation method of the present invention also includes an analysis model preparation step of preparing an analysis model in which the rigid support part is modeled as a rigid body and the press die and the elastic support part are modeled as elastic bodies supported by the rigid support part. The press molding simulation method of the present invention also includes a discretized deflection model preparation step of preparing a discretized displacement distribution, which is a distribution of displacement in each divided region obtained by dividing the planar region of the elastic support part into a finite number of regions, expressed as a product of an initial linear spring constant and a load in each divided region. The press molding simulation method of the present invention also includes a reference model preparation step of preparing a reference displacement distribution, which is a distribution of displacement in each divided region, based on a press molding simulation result by an analysis model or an actual measurement result in a press molding test by a press machine. The press forming simulation method of the present invention also includes a linear spring constant distribution calculation step of correcting the initial linear spring constant distribution based on the difference between the reference displacement distribution and the discretized displacement distribution to calculate a linear spring constant distribution, which is a distribution of a finite number of linear spring constants. In this way, according to the press forming simulation of the present invention, since an actual press forming device is simulated by a simplified discretized deflection model represented by a distribution of a finite number of linear spring constants, the calculation load can be reduced, and a model sufficiently close to the rigidity of the actual press forming device 1 can be created. Therefore, the calculation load can be reduced and the press forming can be accurately simulated.
Hereinafter, an embodiment of the present invention will be described in detail.

(Embodiment)
FIG. 2 is an explanatory diagram of an analysis model 100M. FIG. 3 is an explanatory diagram showing a discrete deflection model M. FIG. 3(A) is an explanatory diagram showing a divided region A _n in a plan view. FIG. 3(B) is an explanatory diagram showing a discrete deflection model M in a front view. FIG. 4 is a flow diagram of a press forming simulation method. FIG. 5 is an explanatory diagram of an elastic support part model 10AM. FIG. 6 is a conceptual diagram of a linear spring constant distribution K _(i,j)dis . FIG. 7 is a flow diagram of a linear spring constant distribution calculation process S5.
Hereinafter, the press-forming simulation method according to this embodiment will be described mainly with reference to the flow chart shown in FIG.

(Press molding simulation method)
The press molding simulation method of this embodiment is a press molding simulation method that predicts changes in the physical quantities of a workpiece W when the workpiece W is pressed at a predetermined load using a press machine 10 equipped with a press die 20 to form a press-molded product.
As shown in FIG. 4, the press forming simulation method according to this embodiment includes a classification process S1, an analysis model preparation process S2, a discretized deflection model preparation process S3, a reference model preparation process S4, and a linear spring constant distribution calculation process S5.
The method may also include a modified discretized deflection model creation step S6 of modifying the discretized deflection model M prepared in the discretized deflection model preparation step S3 based on the linear spring constant distribution K _(i,j)dis calculated in the linear spring constant distribution calculation step S5, to create a modified discretized deflection model MM expressed as the product of the linear spring constant distribution K _(i,j)dis and the load F.
It may also include an elastic-plastic analysis process S7 in which an elastic-plastic analysis of the workpiece W is performed when a load F is applied to the workpiece W using a modified discretized deflection model MM expressed as the product of a linear spring constant distribution and a load F.
Each step of the press molding simulation method will be described below. Unless otherwise specified, each step will be described assuming that the slide 12 and the bolster 11 of the press 10 are classified as the elastic support portion 10A and the other parts are classified as the rigid support portion 10B in the classification step S1.

(Classification process)
First, the press machine 10 is classified into an elastic support portion 10A that elastically supports the press die 20 and a rigid support portion 10B that rigidly supports the elastic support portion 10A (classification step S1).

In detail, for example, the elastic support portion 10A may include the slide 12 or the bolster 11 that directly contacts the press die 20. This allows the range of the press machine 10 that affects the deformation of the press die 20 to be partially modeled as an elastic body. This reduces the calculation load of the press molding simulation method. Note that the elastic support portion 10A may also include a bed 15 that supports the bolster 11.
Specifically, for example, the slide 12 and bolster 11 of the press 10 are classified as an elastic support portion 10A, and the other portions are classified as a rigid support portion 10B.

Furthermore, for example, the rigid support portion 10B may include a crown 14. This allows the area of the press 10 that is expected to have little effect on the deformation of the press die 20 to be partially modeled as a rigid body. This reduces the calculation load of the press molding simulation method.

(Analysis model preparation process)
Next, as shown in FIG. 2, an analytical model 100M is prepared in which the rigid support portion 10B is modeled as a rigid body and the elastic support portion 10A is modeled as an elastic body supported by the rigid support portion 10B (analysis model preparation step S2).
In detail, the elastic support portion 10A may be modeled as an elastic body of, for example, three-dimensional elements such as a solid, two-dimensional elements such as a shell, or one-dimensional elements such as a spring, and may be used as the elastic support portion model 10AM.
In addition, the rigid support 10B may be modeled as a boundary condition that constrains the displacement at the boundary of the elastic support model 10AM (for example, the Young's modulus is set to infinity), and may be used as the rigid support model 10BM. The rigid support model 10BM may be modeled as a rigid body that moves (displaces) in accordance with the movement (displacement) of the elastic support model 10AM at a portion where a force acts on the elastic support model 10AM, while constraining the deformation of the elastic support model 10AM. The rigid support model 10BM may be modeled as a three-dimensional element such as a solid that is in contact with the boundary with the elastic support model 10AM and is set as a rigid body that does not deform even when a load is applied.
2, the analytical model 100M may be configured such that the elastic support part model 10AM is supported by a press die model 20M in which the press die 20 is modeled as, for example, an elastic body. The analytical model 100M may be configured such that both the upper and lower sides of the press die model 20M are supported by the analytical model 100M, and at the same time, the slide 12 may be reproduced by the upper analytical model 100M and the bolster 11 may be reproduced by the lower analytical model 100M.

(Discrete deflection model preparation process)
Next, a discretized deflection model M is prepared in which the discretized displacement distribution ω(i _{,j )dis, which is the planar distribution of the displacement ω(i,j} ) in each divided region A _n obtained by dividing the planar region A of the elastic support part _10A into a finite number n, is expressed as the product of the initial linear spring constant distribution Kinit _{(i,j )dis, which is the planar distribution of the initial linear spring constant Kinit(i,j)} for each divided region A n, and the load F (discretized deflection model preparation step S3).

3A and 3B are explanatory diagrams showing the discretized deflection model M. Fig. 3A is an explanatory diagram showing divided regions in a plan view, and Fig. 3B is an explanatory diagram showing the discretized deflection model M in a front view.
In detail, as shown in Fig. 3(A), a discrete displacement distribution ω _{(i,j)dis, which is the distribution of the displacement ω(i,j)} in each divided region An obtained by dividing the planar region A of the elastic support part _10A into a finite number _n , is prepared, and as shown in Fig. 3(B), a discrete deflection model M is prepared in which the discrete displacement distribution ω( _{i,j )dis} is expressed as the product of the initial linear spring constant distribution Kinit _{(i,j)dis, which is the distribution of the initial linear spring constant Kinit(i,j)} for each divided region An, and the load F. Note that in Fig. 3(A), a rectangular region surrounded by intersecting straight lines represents the divided region An.
For example, the discretized deflection model M can be expressed by the following function:
F/n=K _init(i,j) *ω _(i,j)
F=K _init(i,j)dis *ω _(i,j)dis

(Reference model preparation process)
Next, a reference displacement distribution _{ωref(i,j)dis is prepared, which is a distribution of the displacement ωref(i,j) in} each divided region A _n obtained by dividing the planar region A of the elastic support portion 10A into a finite number of regions, based on the results of a press molding simulation using the analysis model 100M or the results of actual measurements in a press molding test using the press machine 10 (reference model preparation step S4). Hereinafter, the function representing the relationship between the load F and the reference displacement distribution _{ωref(i,j)dis} may be referred to as a reference model _Mref .
The reference model preparation step S4 may be performed in parallel with the discretized deflection model preparation step S3.

In detail, a press molding simulation is performed using the analytical model 100M prepared in the analytical model preparation process S2, and based on the results of the simulation, a reference displacement distribution ω _{ref(i, j) dis is calculated,} which is the distribution of the displacement ω _{ref(i, j} ) in each divided area An obtained by dividing the planar area A of the elastic support part _10A into a finite number of areas.
For example, as shown in FIG. 5, based on the analytical model 100M, the slide 12 and the bolster 11 of the press machine 10 are modeled as elastic bodies, and a reference model M _ref is created with an elastic support part model 10AM composed of a slide model 12AM and a bolster model 11AM. In this case, the elastic support part model 10AM may be, for example, a solid model composed of three-dimensional elements that simulates the shapes of the actual slide 12 and the bolster 11. In the reference model M _ref created based on this analytical model 100M, the upper die model 22M of the press die model 20M is attached to the lower surface of the slide 12. In addition, in the reference model M _ref created based on this analytical model 100M, the lower die model 21M of the press die model 20M is attached to the lower surface of the bolster 11. In the reference model M _ref created based on this analytical model 100M, the workpiece model WM is sandwiched between the upper die model 22M and the lower die model 21M.
Then, a load F is applied from above to below on the upper surface of the slide model 12AM so as to simulate an actual press machine 10. Then, the relative distance between the slide model 12AM and the bolster model 11AM is gradually shortened, and the load F is applied to the workpiece model WM to simulate an actual press forming. At this time, a reference displacement distribution ω _{ref(i, j )dis, which is a distribution of the displacement ω ref(i, j} ) in each divided region A _n , is calculated from the relationship between the load F and the displacement of the slide model 12AM or the bolster model 11AM.

In detail, instead of the method based on the press molding simulation result using the reference model M _ref created based on the above-mentioned analysis model 100M, the displacement of the press machine 10 may be actually measured in a press molding test using the actual press machine 10, and a reference displacement distribution ω _{ref (i, j)} dis , which is a distribution of the displacement ω _{ref (i, j} ) in each divided area A _n obtained by dividing the planar area A of the elastic support part 10A into a finite number of areas, may be calculated based on the actual measurement result. For example, in a press molding test in which a load F is applied to an actual press machine 10 to which a press die 20 that sandwiches a workpiece W is attached, the vertical displacement of the slide 12 or the bolster 11 in the press machine 10 when the load F is applied is actually measured at a plurality of points scattered in a plane, for example, using a displacement meter. Then, a reference displacement distribution ω _{ref (i, j) dis} , which is a distribution of the displacement ω ref (i, _j) in each divided area A _n , may be calculated based on the relationship between the load F and the displacement at the plurality of points.

(Linear spring constant distribution calculation process)
Then, based on the difference between the reference displacement distribution ω _{ref(i, j) dis} and the discretized displacement distribution ω _{(i, j) dis} , the initial linear spring constant distribution K _{init(i, j) dis} is corrected to calculate the linear spring constant distribution K _{(i, j) dis} , which is a distribution of a finite number of linear spring constants (linear spring constant distribution calculation step S5).
In detail, for example, the initial linear spring constant distribution K init _(i,j)dis of the discretized deflection model M is corrected so that the value obtained by subtracting the reference displacement distribution ω _ref(i,j)dis from the discretized displacement distribution ω _(i,j) dis approaches zero. Specifically, for example, the linear spring constant distribution K _(i,j)dis may be calculated by a convergence calculation using a gradient method described later. This makes it possible to calculate the linear spring constant distribution K _(i,j)dis, which is the XY planar distribution of the linear spring constant (Z axis) in each divided region A _n as shown in FIG. 6.

(Convergence calculation using gradient method)
The linear spring constant distribution K _(i,j)dis in the linear spring constant distribution calculation step S5 can be obtained by convergence calculation using a gradient method as described below.
(1) As shown in FIG. 7, first, an initial linear spring constant distribution K _init(i,j)dis for each divided region A _n is provisionally set (initial linear spring constant provisional setting step S51).
(2) Next, a reference displacement distribution ω _ref(i,j)dis is calculated using the reference model M _ref prepared in the reference model preparation step S4 (reference displacement distribution calculation step S52).
(3) In parallel with the reference displacement distribution calculation step S52, the discretized displacement distribution ω _(i,j)dis is calculated using the discretized deflection model M prepared in the discretized deflection model preparation step S3 (discretized displacement distribution calculation step S53).
(4) It is determined whether or not the absolute value of the difference between the discretized displacement distribution ω _{(i, j) dis} and the reference displacement distribution ω _{ref(i, j) dis} exceeds a threshold value tol (threshold value determination step S54).
When the error distribution e _{(i,j)dis, which is the absolute value of the difference between the discretized displacement distribution ω(i,j)dis} and the reference displacement distribution _{ωref(i,j) dis} , exceeds the threshold value tol (for example, when the error e(i _{,j) for each divided area An, which is the absolute value of the difference between the displacement ω(i, j)} for each divided area An and the reference displacement ωref _(i,j) for each divided area An, exceeds the threshold value tol), the error e _(i,j) for each divided area An is multiplied by an arbitrary correction coefficient, and the resultant value is added or subtracted from the initial linear spring constant Kinit _(i,j) in that divided area _An (from the second time onwards, to the corrected linear spring constant K _(i,j) ) to obtain the corrected linear spring constant K _(i,j) in the divided area _An . Then, a corrected linear spring constant distribution K _{(i,j )dis is obtained, which is a set of corrected linear spring constants K(i,j)} for each divided region An. Next, the reference displacement distribution calculation step S52 and the discretized displacement distribution calculation step S53 are performed again.
When the error distribution e( _{i,j) dis} , which is the absolute value of the difference between the discretized displacement distribution ω(i,j)dis and the reference displacement distribution _ωref(i,j) dis, becomes equal to or smaller than the threshold value tol, the process proceeds to a modified discretized deflection model creation process S6 described later.
(5) These steps are repeated until the error distribution e( _{i,j)dis, which is the absolute value of the difference between the discretized displacement distribution ω(i, j )dis and the reference displacement distribution ωref} (i,j)dis, becomes equal to or less than the threshold value tol. Then, the corrected linear spring constant distribution K _(i,j)dis when it becomes equal to or less than the threshold value tol becomes the desired linear spring constant distribution K _(i,j)dis . Therefore, the stiffness of the actual press machine 10 can be represented by a discretized deflection model M including the linear spring constant distribution K _(i,j)dis , which is a planar distribution of a finite number of linear spring constants.

(Modified discrete deflection model creation process)
Next, a modified discretized deflection model MM expressed as the product of the linear spring constant distribution K _(i,j)dis calculated in the linear spring constant distribution calculation step S5 and the load F is created (modified discretized deflection model creation step S6).
In this manner, the modified discretized deflection model MM can be created. Therefore, since the press 10 can be represented by the discretized deflection model M, the calculation load can be reduced and the deformation state of the actual press 10 can be reproduced more accurately. Therefore, the effect of the rigidity of the press 10 can be anticipated in the design of the press die 20, the design of the press-molded product, etc., while suppressing the calculation load.

(Elastic-plastic analysis process)
Using the modified discretized deflection model MM created in the modified discretized deflection model creation step S6, an elastic-plastic analysis is performed on the workpiece model WM that models the workpiece W (elastic-plastic analysis step S7).
In detail, an elastic-plastic _{analysis of the} work model WM is performed when a load F is applied to the work model WM, which is modeled as an elastic-plastic body, using a modified discretized deflection model MM expressed as the product of a linear spring constant distribution K(i,j)dis and a load F.
This makes it possible to anticipate the effect of the rigidity of the press 10 on the deformation of the workpiece model WM while suppressing the calculation load. Therefore, it is possible to design the press die 20 that can form a press-formed product with high precision, and to design the press-formed product with high precision.

(Press molding simulation program)
Next, a press-molding simulation program for causing a computer to execute the above-mentioned press-molding simulation method will be described.
The press forming simulation program causes a computer to execute a linear spring constant distribution calculation step of calculating a linear spring constant distribution K( _{i,j)dis , which} is a distribution of a finite number n of linear spring constants K _(i,j) , based on the difference between the reference displacement distribution ωref _(i,j)dis and the discretized displacement distribution ω(i,j)dis. Note that data of the reference displacement distribution _{ωref(i,j)dis} and the discretized displacement distribution ω _(i,j)dis are stored in advance in a memory so that they can be called up when the press forming simulation program is executed.
In this way, the press molding simulation program can calculate the linear spring constant distribution K _{(i,j )dis, which is the distribution of a finite number n of linear spring constants K(i,j)} , and can therefore be used in CAE, making it possible to design the press die 20 in anticipation of deformation of the press machine 10 while suppressing the calculation load. Therefore, the press die 20 designed in anticipation of deformation of the press machine 10 can manufacture press-molded products with high precision.

(Press molding simulation device)
Next, a press-molding simulation device equipped with the above-mentioned press-molding simulation program will be described.
The press forming simulation device, like a general computer, is equipped with a storage device, a processor, a memory, an interface, and an output device.
In detail, the press forming simulation device is provided with an output device that displays a linear spring constant distribution K _{(i,j )dis, which is a distribution of a finite number n of linear spring constants K(i,j)} .
In this way, since the press molding simulation device is equipped with an output device that displays the linear spring constant distribution K _{(i,j) dis, which is the distribution of a finite number n of linear spring constants K(i,j)} , it can be used in CAE and can design the press die 20 in anticipation of deformation of the press machine 10. Therefore, the press die 20 designed in anticipation of deformation of the press machine 10 can manufacture press-molded products with high precision.

Other Embodiments
Although the embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications and the like are possible.

The press-forming simulation method according to this embodiment is a press-forming simulation method for predicting a change in a physical quantity of a workpiece W when the workpiece W is pressed with a predetermined load F by a press machine 10 equipped with a press die 20 to form a press-formed product. The press-forming simulation method includes a classification step S1 of classifying the press machine 10 into an elastic support portion 10A that elastically supports the press die 20 and a rigid support portion 10B that rigidly supports the elastic support portion 10A, an analytical model preparation step S2 of preparing an analytical model 100M in which the rigid support portion 10B is modeled as a rigid body and the elastic support portion 10A is modeled as an elastic body supported by the rigid support portion 10B, and an analytical model preparation step S3 of preparing an analytical model 100M in which a discretized displacement distribution ω(i,j)dis, which is a distribution of displacement in each divided region A _n obtained by dividing a planar region A of the elastic support portion 10A into a finite number n, is calculated as an initial linear spring constant distribution K _(i,j) which is a distribution of an initial linear spring constant Kinit _(i,j) for each divided region A _n . the step of preparing a discretized deflection model M expressed as the product of the load F and the analytical model preparation step S4 of preparing a reference displacement distribution ω _{ref(i, j ) dis} , which is a distribution of displacement in each divided region A _n , based on the results of a press forming simulation using the analytical model 100M or the results of actual measurement in a press forming test using the press machine 10; and the step of calculating a linear spring constant distribution K init( _{i, j) dis ,} which is a distribution of a finite number n of linear spring constants, by correcting the initial linear spring constant distribution K _{init( i, j) dis based on the difference between the reference displacement distribution ω ref(i, j) dis} and the discretized displacement distribution ω (i, j) dis. As a result, the actual press forming apparatus 1 is simulated by a simplified discrete deflection model M represented by the distribution of a finite number n of linear spring constants K _(i,j) , so that the calculation load can be reduced and a model that is sufficiently close to the rigidity of the actual press forming apparatus 1 can be created. Therefore, a press forming simulation method that can accurately reproduce press forming while reducing the calculation load can be provided.

1 Press molding device 10 Press machine 10A Elastic support part 10AM Elastic support part model 10BM Rigid support part model 11 Bolster 11AM Bolster model 12 Slide 12AM Slide model 13 Drive device 14 Crown 15 Bed 20 Press die 20M Press die model 21 Lower die 21M Lower die model 22 Upper die 22M Upper die model 100M Analysis model A Planar region An Divided region F Load M Discrete deflection model Mref Reference model S1 Classification process S2 Analysis model preparation process S3 Model preparation process S4 Reference model preparation process S5 Constant distribution calculation process S6 Model creation process S7 Elastic-plastic analysis process S51 Initial linear spring constant provisional setting process S52 Reference displacement distribution calculation process S53 Discrete displacement distribution calculation process S54 Threshold judgment process W Work WM Work model

Claims (4)

A press molding simulation method for predicting a change in a physical quantity of a workpiece when the workpiece is pressed at a predetermined load by a press machine equipped with a press die to form a press-formed product, comprising:
a classification step of classifying the press machine into an elastic support part that elastically supports the press die and a rigid support part that rigidly supports the elastic support part;
an analysis model preparation step of preparing an analysis model in which the rigid support portion is modeled as a rigid body and the elastic support portion is modeled as an elastic body supported by the rigid support portion;
a discretized deflection model preparation step of preparing a discretized deflection model in which a discretized displacement distribution, which is a distribution of displacement in each divided region obtained by dividing a planar region of the elastic support part into a finite number of regions, is expressed as a product of an initial linear spring constant distribution, which is a distribution of an initial linear spring constant in each divided region, and the load;
A reference model preparation process for preparing a reference displacement distribution, which is a distribution of displacement in each of the divided regions, based on a press molding simulation result using the analysis model or an actual measurement result in a press molding test using the press;
a linear spring constant distribution calculation step of correcting the initial linear spring constant distribution based on a difference between the reference displacement distribution and the discretized displacement distribution to calculate a linear spring constant distribution that is a distribution of a finite number of linear spring constants;
A press molding simulation method comprising: The press-molding simulation method according to claim 1 , wherein the elastic support portion includes a slide or a bolster that is in direct contact with the press die. The press-molding simulation method according to claim 1 or 2, wherein the rigid support portion includes a crown. The press forming simulation method according to any one of claims 1 to 3, further comprising an elastic-plastic analysis process for performing an elastic-plastic analysis of a work model in which the work is modeled using a modified discretized deflection model expressed as a product of the linear spring constant distribution and the load, when the load is applied to the work model.

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