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

Abstract

Provided are a press forming analysis method, a press forming analysis device, 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 of the present invention is a press forming analysis method that uses the finite element method to predict press forming loads using a mold model 9 having an upper mold model 11 and a lower mold model 17 modeled with shell elements, and includes an elastic element-added lower mold 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 mold model 17 to create an elastic element-added lower mold model 13, an elastic coefficient determination step S3 in which the elastic coefficient to be given to the elastic elements 15 is determined, and a press forming load acquisition step S5 in which press forming analysis is performed using the mold model 9 including the elastic element-added lower mold model 13 modeled in the elastic element-added lower mold model creation step S1, and the press forming load is acquired.

Description

[Technical Field]

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

[0002] The use of high-tensile steel sheets in automobile bodies is expanding due to the growing need for lighter automobiles to improve fuel efficiency and collision safety. However, the application of high-tensile steel sheets faces challenges such as poor formability due to its low ductility and poor dimensional accuracy due to its high material strength.

[0003] Furthermore, when high-tensile steel sheets are press-formed, the press forming load increases, making it necessary to change the press line or separate the parts. This increase in press forming load is also an obstacle to the application of high-tensile steel sheets. Therefore, there is a need for a press forming analysis method that can accurately predict press forming loads in advance.

[0004] It is also known that the forming state of a metal member using a press die varies depending on the structure of the press device. The inventors have confirmed that even when press forming is performed using the same press die, the press forming load varies depending on the structure of the press device. Therefore, in order to accurately predict the press forming load, it is necessary to take into account the structure of the press device.

[0005] In this regard, Patent Document 1 proposes a method of calculating the press forming load from an approximate formula by taking the 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 obtained by forming analysis. Furthermore, Patent Document 2 proposes a method for analyzing press forming that takes into account 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 Summary of the Invention [Problem to be solved by the invention]

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

[0008] The present invention has been made to solve such problems, and aims to provide a press forming analysis method, a press forming analysis device, and a press forming analysis program that can predict press forming loads in advance, even for new part shapes and materials. [Means for solving the problem]

[0009] (1) A press forming analysis method according to the present invention is a method for predicting a press forming load using a die model having an upper die model and a lower die model modeled using shell elements, using a finite element method, a lower die model creation step of modeling a lower structure of a press device using elastic elements and adding the elastic elements to the lower die model to create an elastic element-added lower die model; The method is characterized by including an elastic coefficient determination step of determining an elastic coefficient to be applied to the elastic element, and a press forming load acquisition step of performing press forming analysis using a mold model including the elastic element-applied lower mold model modeled in the elastic element-applied lower mold model creation step, and acquiring the press forming load.

[0010] (2) Furthermore, in the above-described (1), the method for determining the elastic coefficient in the elastic coefficient determination step is characterized in that it is determined by either measuring the distribution of reaction force and displacement of the press device due to the load applied to the actual press device, or modeling the press device with three-dimensional solid elements and determining the distribution of reaction force and displacement by rigidity analysis of the displacement due to the load applied, or modeling the press device with two-dimensional shell elements and determining the distribution of reaction force and displacement by rigidity analysis of the displacement due to the load applied.

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

[0012] (4) Furthermore, in the above (2), the elastic coefficient is a value calculated from the average of the distribution of reaction forces obtained in the elastic coefficient determination process, and is set in the elastic body element.

[0013] (5) Furthermore, in the above-described (1), when the mold is an insert type, only the insert block involved in the actual molding in the lower mold model is modeled by adding elastic elements in the elastic element-adding lower mold model creation process.

[0014] (6) The press forming analysis device according to the present invention predicts a press forming load using a die model having an upper die model and a lower die model modeled using shell elements, an elastic element-imparted lower die model creation unit that models a lower structure of a press device using elastic elements and adds the elastic elements to the lower die model to create an elastic element-imparted lower die model; an elastic coefficient determination unit that determines an elastic coefficient to be applied to the elastic element; and a press-forming load acquisition unit that performs press-forming analysis using a die model including a lower die model with elastic body elements and acquires the press-forming load.

[0015] (7) A press-forming analysis program according to the present invention is characterized in that it causes a computer to function as the press-forming analysis device described in (6) above. [Effects of the Invention]

[0016] According to the present invention, press forming loads can be predicted in advance even for new part shapes and materials through press forming analysis, which in turn makes it possible to appropriately allocate the part forming processes and select the appropriate press equipment for producing the part. [Brief explanation of the drawings]

[0017] [Figure 1] 3 is a flowchart of a press-forming analysis method according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating a press machine and a mold. [Figure 3] FIG. 3 is a diagram showing a mold model obtained by modeling FIG. 2. [Figure 4] 1 is an explanatory diagram of a mold type and a corresponding lower mold model with elastic elements. FIG. [Figure 5] FIG. 10 is an explanatory diagram of a method for determining the elastic modulus. [Figure 6] FIG. 10 is a block diagram showing the configuration of a press-forming analysis device according to a second embodiment. [Figure 7] FIG. 2 is an explanatory diagram of the shape of the part to be molded in Example 1. [Figure 8] FIG. 1 is an explanatory diagram of a mold model used as a conventional example in Example 1. [Figure 9] FIG. 10 is an explanatory diagram of the shape of a part to be molded in Example 2. [Figure 10] FIG. 10 is an explanatory diagram of an actual mold used in Example 2. [Figure 11] FIG. 11 is an explanatory diagram of a die model obtained by modeling the actual die shown in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0018] <Background to the invention> When investigating a press forming analysis method that can predict press forming loads taking into account the structure of a press device using press forming analysis with the finite element method, the inventors first investigated the phenomenon in which the press forming load varies depending on the structure of the press device.

[0019] From press forming tests using actual equipment and examinations using press forming analysis, it was found that the difference in press forming load depending on the structure of the press equipment is due to the difference in the amount of elastic deformation during press forming of the lower structure of the press equipment on which the lower die is installed. In other words, 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 the amount of elastic deformation of this lower structure differs depending on the structure of the press device, and this is the cause of the difference in press forming load. It was also found that the upper structure of the press device also undergoes elastic deformation, but the effect is smaller than that of the lower structure.

[0020] Regarding the elastic deformation of the press machine, press forming analysis has been carried out in which the structure of the press machine is represented using non-rigid solid elements (three-dimensional elements) and the deformation of the press machine is taken into account, but this requires enormous calculation time and is not suitable for practical use. On the other hand, analysis using shell elements, which has a fast calculation time and is used in practice, models only the surface of the die, so it is not possible to reproduce the actual state where the die comes into contact with the lower structure of the press device, and it is not possible to take into account the elastic deformation of the press device.

[0021] Therefore, in order to shorten the calculation time and to express the difference in elastic deformation of the lower structure, we concluded that it would be best to model the lower structure of the press device as an elastic body, set an appropriate elastic coefficient using boundary conditions, and assign it to the shell element mold model.

[0022] The present invention has been made based on the results of the above investigation, and specific embodiments thereof will be described below.

[0023] [Embodiment 1] The press forming analysis method according to this embodiment is a press forming analysis method for predicting press forming loads using a mold model having an upper mold model and a lower mold model modeled with shell elements, and includes a lower mold model creation step (S1) with elastic body elements, an elastic coefficient determination step (S3), and a press forming load acquisition step (S5), as shown in FIG. 1. Each step will be described in detail below.

[0024] <Lower die model creation process with elastic elements> The elastic element-imparted lower die model creation step S1 is a step of creating an elastic element-imparted lower die model by adding the lower structure of the press device as an elastic element to a lower die model modeled with shell elements.

[0025] The actual devices related to the elastic element-added lower mold model creation process S1 are the lower structure of the press machine and the lower mold of the die, so these will be explained based on Figure 2, which shows a schematic diagram of the actual die 1 and the lower structure 7 of the press machine. The mold 1 is composed of an upper mold 3 and a lower mold 5. As shown in FIG. 2, the press device comprises a lower structure 7 and an upper structure (not shown). The lower structure 7 has a riser 7b provided on a bolster 7a, a lower mold 5 is installed on the riser 7b, and an upper mold 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 color of the dashed lines in Figure 2. That is, the light gray dashed line indicates the mold 1 (mold model 9), and the black dashed line indicates 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 with elastic elements attached, and the lower structure 7 is modeled as an elastic body using elastic elements 15 and attached to the lower mold model 17, which is modeled using shell elements.

[0027] Here, differences in the setting method of the elastic element 15 due to differences in the shape of the lower mold 5 will be described with reference to FIG. Fig. 4(a) is a diagram showing the surface of the lower die 5 of the actual die 1, and Fig. 4(b) shows the shape of the back side. In Fig. 4(b), (bA) shows die A (solid) whose back side is solid, and (bB) shows die B (hollow) whose back side is hollow.

[0028] Figure 4(c) is a schematic diagram showing the cross-sectional shapes of mold A and mold B, and a thick black line is provided in the figure to indicate the area where the elastic element 15 is provided 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 comes into contact with the lower structure 7 of the press device over the entire surface, so an elastic element 15 is applied to the entire back surface. On the other hand, as shown in (cB) of Figure 4(c), in the case of mold B, the lower mold 5 comes into contact with the lower structure 7 only at the bottom of the peripheral and central groove-shaped portions, so elastic elements 15 are applied only to the contacting areas.

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

[0030] <Elastic modulus determination process> The elastic modulus determination step S3 is a step of determining the elastic modulus to be applied to the elastic element 15 that models the lower structure 7. The elastic modulus may be determined in the elastic modulus determination step S3 by measuring the distribution of reaction force and displacement occurring in the lower structure 7 of the press due to the actual load applied to the press. Alternatively, a method may be used in which the press device is modeled using three-dimensional solid elements, displacement due to load application is found by rigidity analysis, and the reaction force and displacement distribution at this time are found and used to determine the force distribution. As an example of a specific method for calculating the elastic coefficient in this case, as shown in Figure 5, the lower structure 7 of the press device is modeled using solid elements, and the elastic coefficient is calculated by dividing the sum of the reaction forces generated by pressing the area of ​​the lower mold 5 with forced displacement by the area of ​​contact between the lower mold 5 and the lower structure 7. Furthermore, a method may be used in which the press device is modeled using two-dimensional shell elements, and the distribution of reaction force and displacement due to load application is determined by rigidity analysis.

[0031] Regarding the setting of the elastic coefficient to the elastic element 15, the elastic coefficient 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. In addition, an elastic coefficient calculated from the average value of the reaction forces, which is the sum of the reaction forces generated when a load is applied to the press device divided by the area on which the load is applied, and the displacement, may be set for all elastic elements 15.

[0032] <Press forming load acquisition process> The press-forming load acquisition step S5 is a step of performing a press-forming analysis using the die model 9 including the elastic element-applied lower die model 13, and acquiring 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, the lower structure 7 of the press device is modeled using elastic elements 15 and attached to the lower mold model 17 which is modeled using shell elements, so the calculation time does not become enormous, unlike in press molding analysis which expresses the structure of the press device using non-rigid solid elements (three-dimensional elements) and takes into account deformation of the press device. Furthermore, as a result of being able to predict the press forming load in advance, it becomes possible to appropriately allocate the processes for forming the parts and to select the appropriate press equipment for producing the parts.

[0034] [Embodiment 2] The press forming analysis method described in the first embodiment can be realized by causing a computer to execute a preset program. A press forming analysis device, which is an example of such a device, will be described in this embodiment. As shown in Figure 6, the press molding analysis device 21 of this embodiment is configured by a computer such as a PC (personal computer), and has 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 a processing unit 31, and each function is executed in response to a command from the processing unit 31. Hereinafter, each component of the press forming analysis device 21 according to this embodiment will be described.

[0035] ≪Display device≫ The display device 23 is used to display the analysis results and is configured with a liquid crystal monitor or the like.

[0036] Input Devices The input device 25 is used for displaying instructions for blanks, press-molded products, etc., and for inputting conditions by the operator, and is composed of a keyboard, mouse, etc.

[0037] ≪Storage device≫ The storage device 27 is used to store various files such as CAD data for molds, shape files for blanks and press-molded products, and is configured with a hard disk or the like.

[0038] <Working data memory> The working data memory 29 is used for temporary storage of data used by the arithmetic processing unit 31 and for calculations, and is composed of RAM (Random Access Memory) and the like.

[0039] <<Calculation processing unit>> As shown in FIG. 6, the calculation processing unit 31 has an elastic body-applied lower die model creating unit 33, an elastic coefficient determining unit 35, and a press forming load acquiring unit 37, and is configured by a CPU (Central Processing Unit). Each of these parts functions by the CPU executing a predetermined program. The functions of the above-mentioned sections in the arithmetic processing section 31 will be explained below.

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

[0041] The elastic coefficient determination unit 35 determines the elastic coefficient to be applied to the elastic element 15 that models the lower structure 7, and executes the elastic coefficient determination step S3 described in the first embodiment.

[0042] The press forming load acquisition unit 37 performs press forming analysis using the mold model 9 including the elastic element-added lower mold model 13 to acquire the press forming load, and executes the press forming load acquisition process S5 described in embodiment 1.

[0043] According to the press forming analysis device 21 of this embodiment, as in the first embodiment, even for new part shapes and materials, the press forming load can be predicted in advance, and the calculation time does not become enormous.

[0044] As described above, the elastic body-applied lower die model creation unit 33, the elastic coefficient determination unit 35, and the press forming load acquisition unit 37 in the press forming analysis device 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 causing a computer to function as an elastic body-applied lower die model creation unit 33, an elastic coefficient determination unit 35, and a press forming load acquisition unit 37. [Example]

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

[0046] [Table 1]

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

[0048] [Table 2]

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

[0050] In addition, the load in the actual press forming test for die B was 1286 kN, whereas the press forming load predicted using the conventional method was 4428 kN, resulting in an error of 244% compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (invention example) was 1382 kN, and the error with the actual press forming test was 7%.

[0051] <Pressing device (2)> In press device (2), the actual press forming test load for die A was 2222kN, while the press forming load predicted by the conventional method was 4428kN, with an error of 99% from the actual press forming test. In contrast, the press forming load predicted by the proposed method (invention example) was 2156 kN, and the error with the actual press forming test was 3%.

[0052] In addition, the load in the actual press forming test for die B was 1527kN, whereas the press forming load predicted using the conventional method was 4428kN, resulting in an error of 190% compared to the actual press forming test. In contrast, the press forming load predicted by the proposed method (invention example) was 1619 kN, and the error with the actual press forming test was 6%.

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

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

[0055] As described above, it can be seen that the proposed method (invention example) is extremely superior to the conventional method in all cases. [Example]

[0056] 9 shows the shape of the part to be used in Example 2. The material of the part is a cold-rolled 1470 MPa-class high-tensile steel sheet, and the thickness is 1.2 mm. Figure 10 shows the mold structure of Example 2. The mold of Example 2 has 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 appearance of the insert block 49 part of the punch, and Figure 10(c) shows cross sections of mold C (cC) when the punch is a solid block, and mold D (cD) when the punch is a hollow block.

[0057] Fig. 11 shows a mold model 9 in which only the insert block 49 shown in Fig. 10 is modeled. In Fig. 11, parts corresponding to those in Fig. 3 showing the mold model 9 of Example 1 are given the same reference numerals. FIG. 11(a) is a perspective view of the mold model 9 seen from above, which includes an upper mold model 11, a blank model 51, a blank folder model 53, and a lower mold model 13 with elastic elements. In addition, in the upper model 11 in FIG. 11, each part is colored gray, but this is a specification of the software used and has no special meaning in relation to the present invention.

[0058] FIG. 11(b) shows the mold model 9 as seen from below, FIG. 11(bC) shows mold C which is a solid block, and FIG. 11(bD) shows mold D which is a hollow block.

[0059] The elastic coefficient of the elastic element 15 representing the press device (4) used was determined as the sum of the reaction forces when a displacement was applied to the press device lower structure 7 in an analysis similar to that in Example 1, divided by the installation area between the holder and the insert block 49 of each mold C and D. The elastic modulus that was set is shown in Table 3.

[0060] [Table 3]

[0061] As a conventional example, an analysis was performed 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 used in forming analysis of automobile presses. As in Example 1, a press molding test was also carried out using an actual machine. The analysis results are shown in Table 4.

[0062] [Table 4]

[0063] In the press device (4), the actual press forming test load for die C was 1976 kN, whereas the press forming load predicted by the conventional method was 6214 kN, resulting in an error of 314% from the actual press forming test. In contrast, the press forming load predicted by the proposed method (invention example) was 2065 kN, and the error with the actual press forming test was 5%.

[0064] Furthermore, the load in the actual press forming test for die D was 1885kN, whereas the press forming load predicted using the conventional method was 6214kN, with an error of 330% from the actual press forming test. In contrast, the press forming load predicted by the proposed method (invention example) was 2017 kN, with an error of 7% 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 the invention) had a smaller error with the actual press forming test than the press forming load predicted by the conventional method, demonstrating that the accuracy of press forming load prediction has improved. [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 Elastic body attached lower die model 15 Elastic element 17 Lower model 21 Press forming analysis equipment 23 Display device 25 Input Devices 27 Storage device 29 Working data memory 31 Processing unit 33 Elastic body added lower die model creation section 35 Elastic modulus determination section 37 Press forming load acquisition section 41 Mold model (conventional example) 43 Upper model (conventional example) 45 Lower model (conventional example) 47 Lower structure model (conventional example) 49 Insert Block 51 Blank Model 53 Blank Folder Model

Claims

1. A press forming analysis method for predicting a press forming load using a die model having an upper die model and a lower die model modeled using shell elements by using a finite element method, a lower die model creation step of modeling a lower structure of a press device using elastic elements and adding the elastic elements to the lower die model to create an elastic element-added lower die model; a press-forming analysis method comprising: an elastic coefficient determination step of determining an elastic coefficient to be applied to the elastic element; and a press-forming load acquisition step of performing a press-forming analysis using a die model including the elastic element-added lower die model modeled in the elastic element-added lower die model creation step, and acquiring a press-forming load.

2. The method of determining the elastic modulus in the elastic modulus determination step includes measuring the distribution of reaction force and displacement of a press device due to a load applied to an actual press device. Alternatively, the press equipment can be modeled using three-dimensional solid elements, and the displacement due to the load applied can be calculated using rigidity analysis, and the distribution of reaction force and displacement at this time can be calculated. Alternatively, the press forming analysis method according to claim 1 is characterized in that the determination is made by either of the following: modeling the press device with two-dimensional shell elements, determining the displacement due to the load application by rigidity analysis, and determining the distribution of reaction force and displacement at this time.

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

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

5. 2. The press molding analysis method according to claim 1, wherein, when the mold is an insert type, only the insert block involved in the actual molding in the lower mold model is modeled by adding elastic elements in the elastic element-added lower mold model creation process.

6. A press forming analysis device that predicts a press forming load using a die model having an upper die model and a lower die model modeled using shell elements, an elastic element-imparted lower die model creation unit that models a lower structure of a press device using elastic elements and adds the elastic elements to the lower die model to create an elastic element-imparted lower die model; an elastic coefficient determination unit that determines an elastic coefficient to be applied to the elastic 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 and acquires a press-forming load.

7. A press-forming analysis program that causes a computer to function as the press-forming analysis device according to claim 6.

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