Press forming analysis method, press forming analysis apparatus, and press forming analysis program

Abstract

This invention provides a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program that can predict press forming loads in advance, even for new part shapes and materials. [Solution] The press forming analysis method according to the present invention is a press forming analysis method that predicts the press forming load using a die model 9 having an upper die model 11 and a lower die model 17 modeled with shell elements, using the finite element method, and includes: an elastic element-attached lower die model creation step S1 in which the lower structure 7 of the press device is modeled with elastic elements 15 and attached to the lower die model 17 to create an elastic element-attached lower die model 13; an elastic modulus determination step S3 in which the elastic modulus to be applied to the elastic elements 15 is determined; and a press forming load acquisition step S5 in which press forming analysis is performed using the die model 9 including the elastic element-attached lower die model 13 modeled in the elastic element-attached lower die model creation step S1, and the press forming load is obtained.

Description

Technical Field

[0001] The present invention relates to a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program that can predict a press forming load acting on a press die associated with press working of a metal member. Here, the metal member may be a plate made of various metals such as a hot-rolled steel sheet, a cold-rolled steel sheet, or a surface-treated steel sheet obtained by subjecting a steel sheet to surface treatment (electro-galvanizing, hot-dip galvanizing, organic coating treatment, etc.), SUS, aluminum, magnesium, and the like.

Background Art

[0002] Due to the increasing needs for improving fuel efficiency and collision safety by reducing the weight of automobiles, the application of high-tensile steel sheets in automobile bodies has been expanding. The deterioration of formability due to the low ductility of high-tensile steel sheets and the deterioration of dimensional accuracy due to high material strength are issues for applying high-tensile steel sheets.

[0003] In addition, when press forming a high-tensile steel sheet, the press forming load increases, so it is necessary to change the press line or divide the parts. Such an increase in the press forming load is also an inhibiting factor for applying high-tensile steel sheets. Therefore, there is a need for a press forming analysis method that can accurately predict the press forming load in advance.

[0004] Also, it is known that the formed state of a metal member by a press die varies depending on the structure of the press device. The inventors have confirmed that even in press forming using the same press die, the press forming load differs depending on the difference in the structure of the press device, and it is necessary to consider the structure of the press device for accurate prediction of the press forming load.

[0005] In this regard, Patent Document 1 proposes a method of obtaining a correlation between the forming load at the bottom dead center of the press in an actual machine and the forming load at the stroke before the bottom dead center of the press by forming analysis, and obtaining the press forming load from the approximate formula. Also, Patent Document 2 proposes a method of press forming analysis considering the elastic deformation of the press device. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5610574 [Patent Document 2] Japanese Patent Publication No. 2022-121024 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 requires results of press forming loads from an actual machine, and it is not possible to predict the press forming load for new part shapes and materials in advance. Furthermore, Patent Document 2 describes a method that applies the elastic deformation of a press device when a constant load is applied as the deformation of the press die shape to the forming analysis, and it is not possible to predict the press forming load.

[0008] This invention was made to solve the aforementioned problems and aims to provide a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program that can predict the press forming load in advance, even for novel part shapes and materials. [Means for solving the problem]

[0009] (1) The press forming analysis method according to the present invention is a method for predicting press forming load using a die model having an upper die model and a lower die model modeled with shell elements, using the finite element method, A process for creating a lower die model with elastic elements, which involves modeling the lower structure of a press machine with elastic elements and applying them to the lower die model to create a lower die model with elastic elements, The present invention is characterized by including an elastic modulus determination step of determining the elastic modulus to be applied to the elastic element, and a press forming load acquisition step of performing a press forming analysis using a mold model that includes the elastic element application lower mold model modeled in the elastic element application lower mold model creation step, and obtaining the press forming load.

[0010] (2) Furthermore, in the present invention, the method for determining the elastic modulus in the elastic modulus determination step is characterized by determining it by measuring the distribution of reaction force and displacement of the press device due to the loading of a load onto the actual press device, or by modeling the press device with three-dimensional solid elements and determining the distribution of reaction force and displacement due to the loading of a load by stiffness analysis, or by modeling the press device with two-dimensional shell elements and determining the distribution of reaction force and displacement due to the loading of a load by stiffness analysis.

[0011] (3) Furthermore, in the case described in (2) above, the elastic modulus is calculated from the distribution of reaction forces obtained in the elastic modulus determination step and set to the elastic element at the corresponding position.

[0012] (4) Furthermore, in the case described in (2) above, the elastic modulus is a value calculated from the average of the reaction force distribution obtained in the elastic modulus determination step and is set in the elastic element.

[0013] (5) Furthermore, in the case of the mold described in (1) above, when the mold is of the insert type, the elastic element is added and modeled in the lower mold model creation process only for the insert block that is actually involved in molding in the lower mold model.

[0014] (6) Furthermore, the press forming analysis apparatus according to the present invention predicts the press forming load using a die model having an upper die model and a lower die model modeled with shell elements, Model the lower structure of the press device with elastic body elements, and create a lower die model with elastic body elements attached by applying it to the lower die model. An elastic body element application lower die model creation unit An elastic coefficient determination unit that determines the elastic coefficient to be applied to the elastic body element A press forming load acquisition unit that performs press forming analysis using a die model including a lower die model with elastic body elements attached and acquires a press forming load. It is characterized by including these

[0015] (7) Further, the press forming analysis program according to the present invention causes a computer to function as the press forming analysis device described in (6) above.

Effect of the Invention

[0016] According to the present invention, even for a new part shape or material, the press forming load can be predicted in advance by press forming analysis. As a result, it becomes possible to appropriately allocate the process of forming the part and select an appropriate press device for producing the part.

Brief Description of the Drawings

[0017] [Figure 1] It is a flowchart of the press forming analysis method according to Embodiment 1. [Figure 2] It is a diagram schematically showing a press device and a die. [Figure 3] It is a diagram showing a die model obtained by modeling Figure 2. [Figure 4] It is an explanatory diagram of the type of die and the lower die model with elastic body elements attached corresponding thereto. [Figure 5] It is an explanatory diagram of the method for determining the elastic coefficient. [Figure 6] It is a block diagram showing the configuration of the press forming analysis device according to Embodiment 2. [Figure 7] It is an explanatory diagram of the part shape to be formed in Example 1. [Figure 8] It is an explanatory diagram of the die model used as a conventional example in Example 1. [Figure 9] It is an explanatory drawing of the part shape to be molded in Example 2. [Figure 10] It is an explanatory drawing of the actual mold used in Example 2. [Figure 11] It is an explanatory drawing of a mold model obtained by modeling the actual mold shown in FIG. 10.

Mode for Carrying Out the Invention

[0018] <Background of the Invention> In studying a press forming analysis method capable of predicting a press forming load in consideration of the structure of a press device using a press forming analysis using the finite element method, the inventors first examined the phenomenon that the press forming load differs depending on the structure of the press device.

[0019] From press forming tests using an actual machine and investigations by press forming analysis, it was found that the difference in the press forming load due to the structure of the press device is caused by differences in the amount of elastic deformation during press forming of the lower structure of the press device on which the lower die is installed. That is, when the press die elastically deforms due to the reaction force during press forming, the lower structure of the press device on which the press die is installed also elastically deforms, but depending on the structure of the press device, there are differences in the amount of elastic deformation of this lower structure, which is the cause of the difference in the press forming load. It was also found that although the upper structure of the press device also elastically deforms, its influence is smaller than that of the lower structure.

[0020] Regarding the elastic deformation of the press device, press forming analysis that expresses the structure of the press device with non-rigid solid elements (three-dimensional elements) and considers the deformation of the press device has been carried out, but the calculation time becomes extremely long and it is not suitable for practical use. On the other hand, in analysis using shell elements, which is fast in calculation time and is used practically, since only the surface of the mold is modeled, the actual state where the mold and the lower structure of the press device contact cannot be reproduced, and the elastic deformation of the press device cannot be considered.

[0021] Therefore, in order to shorten the calculation time and represent the differences in elastic deformation of the lower structure, we concluded that the lower structure of the press machine should be modeled as an elastic body, an appropriate elastic modulus should be set by boundary conditions, and this modulus should be applied to the mold model of the shell element.

[0022] The present invention is based on the above-mentioned findings, and specific embodiments are shown below.

[0023] [Embodiment 1] The press forming analysis method according to this embodiment is a press forming analysis method that predicts the press forming load using a die model having an upper die model and a lower die model modeled with shell elements, and as shown in Figure 1, includes a step of creating a lower die model with elastic elements (S1), a step of determining the elastic modulus (S3), and a step of obtaining the press forming load (S5). The following describes each step in detail.

[0024] <Process for creating a lower mold model with elastic elements> Step S1, which involves creating a lower die model with elastic elements, is a process in which the lower structure of the press machine is used as an elastic element and is added to the lower die model, which is modeled using shell elements, in order to create a lower die model with elastic elements.

[0025] The actual equipment involved in the process S1 of creating the lower mold model with elastic elements consists of the lower structure of the press machine and the lower mold of the die. These will be explained based on Figure 2, which schematically shows the actual die 1 and the lower structure 7 of the press machine. Mold 1 consists of an upper mold 3 and a lower mold 5. As shown in Figure 2, the press apparatus comprises a lower structure 7 and an upper structure (not shown). The lower structure 7 has a riser 7b on top of a bolster 7a, a lower die 5 is installed on the riser 7b, and an upper die 3 is attached to the upper structure.

[0026] Figure 3 is a model of Figure 2, and the color coding of the dashed lines in Figure 2 corresponds to the colors of the dashed lines in Figure 2. In other words, the light gray dashed line represents mold 1 (mold model 9), and the black dashed line represents the lower structure 7 of the press device (elastic element 15). As shown in Figure 3, the mold model 9 consists of an upper mold model 11 and a lower mold model 13 to which elastic elements are attached. The lower structure 7 is modeled as an elastic body with elastic elements 15 and attached to the lower mold model 17, which is modeled with shell elements.

[0027] Here, the differences in the method of setting the elastic element 15 due to the difference in the shape of the lower mold 5 will be explained based on Figure 4. Figure 4(a) shows the surface of the lower mold 5 of the actual mold 1, and Figure 4(b) shows the shape of the back side. In Figure 4(b), (bA) shows mold A (solid) where the back side is solid, and (bB) shows mold B (hollow) where the back side is hollow.

[0028] Figure 4(c) schematically shows the cross-sectional shapes of mold A and mold B, with a thick black line indicating the location where the elastic element 15 is attached between the lower structure 7 and the lower mold 5. As shown in (c-A) of Figure 4(c), in the case of mold A, the lower mold 5 is in contact with the lower structure 7 of the press device over its entire surface, so an elastic element 15 is provided on the entire surface of the back side. On the other hand, as shown in (cB) of Figure 4(c), in the case of mold B, the lower mold 5 contacts the lower structure 7 only at the bottom of the surrounding groove-shaped part in the center, so elastic elements 15 are provided only at the contact points.

[0029] Figure 4(d) shows the back surface of the lower mold model 13 with elastic elements 15 attached to the areas shown in Figure 4(c). In (dA) of Figure 4(d), it can be seen that the elastic elements 15 are attached to the entire back surface of the lower mold model 13, and in (dB), it can be seen that the elastic elements 15 are attached to the periphery and the back surface of the central groove bottom of the lower mold model 13.

[0030] <Process for determining the elastic modulus> The elastic modulus determination step S3 is a step in which the elastic modulus to be applied to the elastic element 15 that models the lower structure 7 is determined. One method for determining the elastic modulus in the elastic modulus determination process S3 is to measure and determine the distribution of reaction forces and displacements generated in the lower structure 7 of the press device due to the actual load applied to the press device. Alternatively, the press machine can be modeled using three-dimensional solid elements, the displacement due to load application can be determined by stiffness analysis, and the distribution of reaction forces and displacements at that time can be determined and decided upon. As an example of a specific method for calculating the elastic modulus in this case, as shown in Figure 5, the lower structure 7 of the press machine is modeled with solid elements, and the elastic modulus is obtained by dividing the sum of the reaction forces generated by forcing displacement into the area of ​​the lower die 5 by the area in contact between the lower die 5 and the lower structure 7. Alternatively, the press machine can be modeled using two-dimensional shell elements, and the distribution of reaction forces and displacements due to load application can be determined by stiffness analysis.

[0031] Regarding the setting of the elastic modulus to the elastic element 15, the elastic modulus calculated from the reaction force and displacement at each measurement position when a load is applied to the press device may be set to the elastic element 15 at the corresponding position. Alternatively, the elastic modulus, calculated from the average value of the reaction forces obtained by dividing the sum of the reaction forces generated when a load is applied to the press device by the area under load, and the resulting displacement, may be set for all elastic elements 15.

[0032] <Press forming load acquisition process> The press forming load acquisition process S5 is a process in which press forming analysis is performed using the die model 9, which includes the lower die model 13 with elastic elements, to acquire the press forming load.

[0033] According to the press forming analysis method of this embodiment, the press forming load can be predicted in advance, even for new part shapes and materials. Furthermore, since the lower structure 7 of the press device is modeled with elastic elements 15 and attached to the lower die model 17, which is modeled with shell elements, the computation time does not become enormous, unlike press forming analysis which represents the structure of the press device with non-rigid solid elements (three-dimensional elements) and considers the deformation of the press device. Furthermore, the ability to predict the press forming load in advance allows for the appropriate allocation of processes for forming parts and the selection of the appropriate press equipment for producing parts.

[0034] [Embodiment 2] The press forming analysis method described in Embodiment 1 can be realized by having a computer execute a pre-set program. An example of such a device, a press forming analysis device, is described in this embodiment. As shown in Figure 6, the press forming analysis apparatus 21 according to this embodiment is composed of a computer such as a PC (personal computer) and includes a display device 23, an input device 25, a storage device 27, a working data memory 29, and an arithmetic processing unit 31. The display device 23, input device 25, storage device 27, and working data memory 29 are connected to the arithmetic processing unit 31, and their respective functions are executed by commands from the arithmetic processing unit 31. The following describes the various components of the press forming analysis apparatus 21 according to this embodiment.

[0035] ≪Display device≫ The display device 23 is used for displaying analysis results, etc., and is composed of a liquid crystal monitor or the like.

[0036] <<Input Device>> The input device 25 is used for displaying instructions for blanks, press-formed products, etc., and for inputting conditions by the operator, and consists of a keyboard, mouse, etc.

[0037] ≪Storage device≫ The storage device 27 is used to store various files such as mold CAD data, blanks, and shape files of press-formed products, and is composed of a hard disk or the like.

[0038] ≪Working Data Memory≫ The working data memory 29 is used for temporary storage and calculation of data used by the arithmetic processing unit 31, and is composed of RAM (Random Access Memory), etc.

[0039] <<Processing Unit>> As shown in Figure 6, the arithmetic processing unit 31 includes an elastic body application lower die model creation unit 33, an elastic modulus determination unit 35, and a press forming load acquisition unit 37, and is composed of a CPU (Central Processing Unit). Each of these parts functions when the CPU executes a predetermined program. The functions of each of the above-mentioned parts in the arithmetic processing unit 31 are described below.

[0040] The elastic body-adding lower die model creation unit 33 creates an elastic body-adding lower die model 13 by adding the lower structure 7 of the press device as an elastic body element 15 to the lower die model 17 modeled with shell elements, and executes the elastic body-adding lower die model creation step S1 described in Embodiment 1. The mold model 9, consisting of the upper mold 3 and lower mold 5, is created by a mold model creation unit (not shown) using shell elements.

[0041] The elastic modulus determination unit 35 determines the elastic modulus to be applied to the elastic element 15 that models the lower structure 7, and performs the elastic modulus determination step S3 described in Embodiment 1.

[0042] The press forming load acquisition unit 37 performs press forming analysis using the mold model 9, which includes the lower mold model 13 with elastic elements, and acquires the press forming load. It then executes the press forming load acquisition process S5 described in Embodiment 1.

[0043] According to the press forming analysis apparatus 21 of this embodiment, similar to Embodiment 1, the press forming load can be predicted in advance even for new part shapes and materials, and the calculation time does not become excessively long.

[0044] As described above, the elastic body application lower die model creation unit 33, the elastic modulus determination unit 35, and the press forming load acquisition unit 37 in the press forming analysis apparatus 21 of this embodiment are realized by the CPU executing a predetermined program. Therefore, the press forming analysis program according to the present invention can be specified as one which causes a computer to function as an elastic body application lower die model creation unit 33, an elastic modulus determination unit 35, and a press forming load acquisition unit 37. [Examples]

[0045] To confirm the effects of the present invention, a specific press forming analysis was performed, which is described below. Figure 7 shows the shape of the part targeted in Example 1. The material of the part is cold-rolled 1180 MPa class high-tensile steel sheet, with a thickness of 1.6 mm. As an example of the invention, a mold model 9 including the lower mold model 13 with elastic elements shown in Figure 3 was used. Three types of press devices of different sizes (press devices (1), (2), and (3)) were assumed, and as mold types, a solid A type (mold A) and a hollow B type (mold B) as shown in Figure 4 were used. The elastic modulus of the elastic elements 15 of press devices (1), (2), and (3) was set to the values ​​shown in Table 1. As explained in Figure 5, the elastic modulus was calculated by modeling the lower structure 7 of the press machine with solid elements and dividing the sum of the reaction forces generated by forcing displacement into the area of ​​the die 1 by the area in contact between the die 1 and the lower structure 7.

[0046] [Table 1]

[0047] Furthermore, as a conventional example, we performed an analysis using die model 41, which is currently commonly used in the forming analysis of automotive presses, and in which the upper die 3 and lower die 5 of the press die are modeled as rigid bodies of shell elements. This conventional die model 41 is shown in Figure 8. The upper die model 43 and lower die model 45 are shell elements, and the substructure model 47 is also modeled as a rigid body of shell elements. We also conducted press molding tests using actual equipment. The analysis results are shown in Table 2.

[0048] [Table 2]

[0049] <Pressing device (1)> In the press forming test of mold A in press machine (1), the actual load was 1630kN, while the press forming load predicted by the conventional method was 4428kN, resulting in an error of 171% compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 1747kN, resulting in a 7% error compared to the actual press forming test.

[0050] Furthermore, while the actual press forming load for mold B was 1286kN, the press forming load predicted using the conventional method was 4428kN, resulting in a 244% error compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 1382kN, resulting in a 7% error compared to the actual press forming test.

[0051] <Pressing device (2)> In press machine (2), the actual press forming load for mold A was 2222kN, while the press forming load predicted by the conventional method was 4428kN, resulting in a 99% error compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 2156 kN, resulting in a 3% error compared to the actual press forming test.

[0052] Furthermore, while the actual press forming load for mold B was 1527kN, the press forming load predicted using the conventional method was 4428kN, resulting in a 190% error compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 1619 kN, resulting in a 6% error compared to the actual press forming test.

[0053] <Pressing device (3)> In the press machine (3), the actual press forming load of mold A was 1563kN, while the press forming load predicted by the conventional method was 4428kN, resulting in an error of 183% compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 1535kN, resulting in a 2% error compared to the actual press forming test.

[0054] Furthermore, while the actual press forming load for mold B was 1323kN, the press forming load predicted using the conventional method was 4428kN, resulting in a 235% error compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 1296 kN, resulting in a 2% error compared to the actual press forming test.

[0055] As described above, it is clear that the proposed method (example of invention) is extremely superior to conventional methods in all cases. [Examples]

[0056] Figure 9 shows the shape of the part used in Example 2. The part is made of cold-rolled 1470 MPa class high-tensile steel sheet with a thickness of 1.2 mm. Figure 10 shows the mold structure of Example 2. The mold of Example 2 is a divided structure using an insert method. Figure 10(a) shows the upper mold 3 (die), and the part to be molded is the insert block 49. Figure 10(b) shows the external appearance of the insert block 49 part of the punch, and Figure 10(c) shows the cross-section of mold C (cC) when the punch is a solid block and mold D (cD) when the punch is a hollow block.

[0057] Figure 11 shows a mold model 9 that models only the insert block 49 shown in Figure 10. In Figure 11, the parts corresponding to those in Figure 3, which shows the mold model 9 of Example 1, are denoted by the same reference numerals. Figure 11(a) is a perspective view of the mold model 9 from above, and includes an upper mold model 11, a blank model 51, a blank folder model 53, and an elastic element-added lower mold model 13. Note that in Figure 11, the upper model 11 is color-coded in gray by part, but this is due to the specifications of the software used and has no special significance in relation to the present invention.

[0058] Figure 11(b) shows the mold model 9 viewed from below, with Figure 11(bC) showing mold C, which is a solid block, and Figure 11(bD) showing mold D, which is a hollow block.

[0059] The elastic modulus of the elastic element 15 representing the press device (4) used was calculated by dividing the sum of the reaction forces when displacement was applied to the lower structure 7 of the press device in the same analysis as in Example 1 by the contact area between the insert block 49 of molds C and D and the holder. The set elastic modulus is shown in Table 3.

[0060] [Table 3]

[0061] Furthermore, as a conventional example, we performed an analysis using a die model in which the upper and lower insert blocks 49 of the press die are modeled as rigid bodies of shell elements, which is currently commonly applied in the forming analysis of automotive presses. Furthermore, similar to Example 1, press molding tests using an actual machine were also conducted. The analysis results are shown in Table 4.

[0062] [Table 4]

[0063] In the press machine (4), the actual press forming load of mold C was 1976kN, while the press forming load predicted by the conventional method was 6214kN, resulting in an error of 314% compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 2065 kN, resulting in a 5% error compared to the actual press forming test.

[0064] Furthermore, while the actual press forming load for mold D was 1885kN, the press forming load predicted using the conventional method was 6214kN, resulting in a 330% error compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (example of invention) was 2017 kN, resulting in a 7% error compared to the actual press forming test.

[0065] As described above, under all conditions, the press forming load predicted by the proposed method (example of invention) showed less error compared to the press forming load predicted by the conventional method compared to the actual press forming test, demonstrating an improvement in the accuracy of press forming load prediction. [Explanation of Symbols]

[0066] 1. Mold 3 Upper mold 5 Lower mold 7 Lower structure 7a Bolster 7b Liza 9. Mold Model 11 Upper Model 13. Model with elastic material added to the lower mold 15 Elastic elements 17 Lower model 21 Press forming analysis device 23 Display device 25 Input devices 27 Storage device 29 Working data memory 31. Arithmetic Processing Unit 33. Model creation section for creating elastic body-applied molds 35 Elastic Modulus Determination Section 37 Press forming load acquisition section 41. Mold Model (Conventional Example) 43 Upper model (conventional example) 45 Lower-type model (conventional example) 47 Substructure Model (Conventional Example) 49 Insert Blocks 51 Blank Models 53 Blank Folder Model

Claims

1. A press forming analysis method that uses the finite element method to predict press forming load using a die model having an upper die model and a lower die model modeled with shell elements, A process for creating a lower die model with elastic elements, which involves modeling the lower structure of a press machine with elastic elements and applying them to the lower die model to create a lower die model with elastic elements, A press forming analysis method characterized by comprising: an elastic modulus determination step of determining the elastic modulus to be applied to the elastic element; and a press forming load acquisition step of performing a press forming analysis using a mold model including the elastic element application lower mold model modeled in the elastic element application lower mold model creation step, and obtaining the press forming load.

2. The method for determining the elastic modulus in the elastic modulus determination step involves measuring the distribution of reaction force and displacement of the press device due to the load applied to the actual press device. Alternatively, the press machine can be modeled using three-dimensional solid elements, the displacement due to load application can be determined by stiffness analysis, and the distribution of reaction forces and displacements can be calculated. Alternatively, the press forming analysis method according to claim 1 is characterized by determining the method by either modeling the press apparatus with two-dimensional shell elements, determining the displacement due to load application by stiffness analysis, and determining the distribution of reaction force and displacement at that time.

3. The press forming analysis method according to claim 2, characterized in that the elastic modulus is calculated from the distribution of reaction forces obtained in the elastic modulus determination step and set to the elastic element at the corresponding position.

4. The press forming analysis method according to claim 2, characterized in that the elastic modulus is a value calculated from the average of the reaction force distribution obtained in the elastic modulus determination step and set as an elastic element.

5. The press molding analysis method according to claim 1, characterized in that, in the case of an insert-type mold, the only insert blocks involved in the actual molding process in the lower mold model creation step that are modeled with elastic elements are those that are actually involved in molding in the lower mold model.

6. A press forming analysis apparatus for predicting press forming load using a mold model having an upper mold model and a lower mold model modeled with shell elements, An elastic element-attached lower die model creation unit creates an elastic element-attached lower die model by modeling the lower structure of the press machine with elastic elements and attaching them to the lower die model, An elastic modulus determination unit that determines the elastic modulus to be applied to the elastic element, A press forming analysis apparatus characterized by including a press forming load acquisition unit that performs press forming analysis using a mold model including an elastic element lower die model and acquires the press forming load.

7. A press forming analysis program characterized by causing a computer to function as a press forming analysis apparatus as described in claim 6.

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