Intermediate shape calculation device and intermediate shape calculation method

Abstract

This method calculates an intermediate shape for a forged product that can reduce the forming energy generated during the forging process. [Solution] The intermediate shape calculation device 1 according to the embodiment calculates the forming energy from the initial shape to the final shape using the design data of the initial shape of the forged product, the design data of the intermediate shape before modification, and the design data of the final shape. The intermediate shape calculation device 1 also calculates the amount of shape displacement from the initial shape to the final shape. The intermediate shape calculation device 1 determines the convergence of the objective function obtained from the forming energy and the amount of shape displacement, and if the objective function has not converged, it calculates an intermediate shape that reduces the objective function, sets the diffusion coefficient of the reaction-diffusion equation in the method at a desired part of the intermediate shape, and updates the design data before modification to the design data after modification of the calculated intermediate shape based on the reaction-diffusion equation with the set diffusion coefficient.

Description

[Technical Field] 【0001】 This disclosure relates to an intermediate shape calculation apparatus and an intermediate shape calculation method. [Background technology] 【0002】 Patent Document 1 discloses a method for determining the shape of a forged product, which involves determining the intermediate shape in a previous process from the final shape of the forged product (or the intermediate shape in an intermediate process). In Patent Document 1, the shapes of multiple previously forged products, each with a known shape corresponding to a predetermined process, and the shapes in the preceding processes for each of these products are stored in a database. 【0003】 In this method, the similarity between a newly forged product and a previously stored set of forged products is evaluated, and the shape of the previously forged product with a high degree of similarity is selected as the shape of the newly forged product in the previous process. Furthermore, Patent Document 1 describes a method for determining the shape of the newly forged product in the previous process by selecting multiple shapes when selecting the shape of the previously forged product in the previous process, and then combining these selected shapes from the previously forged products in the previous process. [Prior art documents] [Patent Documents] 【0004】 [Patent Document 1] Japanese Patent Application Publication No. 9-234535 [Overview of the project] [Problems that the invention aims to solve] 【0005】 However, with the technology described in Patent Document 1, if data on previously forged products similar to the new forged product is not stored in the database, it is not possible to determine a good intermediate shape in the preceding process for the new forged product. Furthermore, the shape obtained by combining the preceding process shapes of multiple previously forged products is not necessarily capable of reducing the forming energy generated in the forging process of the new forged product. In addition, because the shape definition using the level set method is not considered, the outer diameter of the calculated shape may be larger than the mold, or shape constraints that take knockout into account cannot be applied, resulting in an unintended shape. 【0006】 This invention has been made in view of these problems, and one of its objectives is to calculate an intermediate shape of a forged product that can reduce the forming energy generated in the forging process. [Means for solving the problem] 【0007】 An intermediate shape calculation device according to one embodiment is an intermediate shape calculation device that repeatedly calculates design data showing the intermediate shape of a forged product and identifies design data showing the final intermediate shape, An acquisition unit that acquires design data for the initial shape of the forged product, design data for the intermediate shape before modification, and design data for the final shape, A molding energy calculation unit calculates the molding energy from the initial shape to the final shape using the acquired design data, A displacement calculation unit that calculates the amount of shape displacement from the initial shape to the final shape, A determination unit that determines whether the amount of change in the objective function, which is obtained from the molding energy and the amount of shape displacement, is less than or equal to a predetermined value, determines whether the objective function converges. If the objective function has not converged, an intermediate shape calculation unit calculates an intermediate shape that reduces the objective function, An update unit that sets the diffusion coefficient of the reaction-diffusion equation in the level-set method at a desired location of the intermediate shape, and updates the pre-modification design data to the calculated post-modification design data of the intermediate shape based on the reaction-diffusion equation with the set diffusion coefficient, It is equipped with these features. 【0008】 An intermediate shape calculation method according to one embodiment is an intermediate shape calculation method that repeatedly calculates design data showing the intermediate shape of a forged product to identify design data showing the final intermediate shape, Computers The steps include obtaining design data for the initial shape of the forged product, design data for the intermediate shape before modification, and design data for the final shape. A step of calculating the molding energy from the initial shape to the final shape using the acquired design data, A step of calculating the amount of shape displacement from the initial shape to the final shape, A step of determining the convergence of the objective function based on whether the amount of change in the objective function, which is obtained from the molding energy and the amount of shape displacement, is less than or equal to a predetermined value, If the objective function has not converged, the steps include calculating an intermediate shape that reduces the objective function, The steps include setting the diffusion coefficient of the reaction-diffusion equation in the level-set method at a desired location of the intermediate shape, and updating the pre-modification design data based on the reaction-diffusion equation with the set diffusion coefficient, Execute this. [Effects of the Invention] 【0009】 According to the present invention, it is possible to calculate the intermediate shape of a forged product, which can reduce the forming energy generated in the forging process. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a block diagram showing the functional configuration of the intermediate shape calculation device according to the embodiment. [Figure 2] This is a flowchart illustrating the intermediate shape calculation method according to the embodiment. [Figure 3] This diagram illustrates an example of shape definition using the level set method. [Figure 4] This diagram illustrates the shape changes of a forged product during the forging process. [Figure 5]This is a diagram for explaining the load generated in the forging process when forming an optimized intermediate shape. [Figure 6] This is a diagram for explaining the forming energy generated in the forging process when forming an optimized intermediate shape. Mode for Carrying Out the Invention 【0011】 Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are appropriately omitted and simplified. Also, in each drawing, the same elements are denoted by the same reference numerals, and duplicate explanations are omitted as necessary. 【0012】 FIG. 1 is a block diagram showing the functional configuration of an intermediate shape calculation device 1 according to an embodiment. The intermediate shape calculation device 1 calculates design data of an intermediate shape between an initial shape, which is the shape of a forging before forging, and a final shape, which is the shape after forging. The intermediate shape calculation device 1 is used, for example, in product design in the forging process of vehicle parts. 【0013】 First, the forging process will be described. In the embodiment, hot die forging, which performs die forming on a billet, is used in the forging process. The billet is a raw material for vehicle parts. As the billet, for example, a rod-shaped or wire-shaped metal material processed to a predetermined size is used. 【0014】 Normally, when manufacturing a product by forging, forging operations are performed step by step using a die for the intermediate shape in the intermediate process. The forging process includes, for example, a first intermediate process, a second intermediate process, and a finishing process. The first intermediate process is a so-called upsetting process that compresses a billet having an initial shape and transforms it into a first intermediate shape. 【0015】 The second intermediate process is a roughing process in which the crushed billet is deformed into a rough material having a second intermediate shape by pre-forming using a roughing die. The finishing process is a process in which the rough material is deformed into the final shape using a finishing die. In this disclosure, the first intermediate process and the second intermediate process are collectively referred to as the "intermediate process," and the first intermediate shape and the second intermediate shape are collectively referred to as the "intermediate shape." 【0016】 As shown in Figure 1, the intermediate shape calculation device 1 comprises a processing unit 10, a storage unit 20, and an input / output unit 30. The processing unit 10 includes a shape calculation function and a 3D data generation function. The shape calculation function is a function that uses so-called topology optimization to calculate setting data for an intermediate shape in order to reduce the forming energy generated by forging. 【0017】 In this embodiment, the shape calculation function repeatedly calculates design data representing intermediate shapes to identify design data representing the final intermediate shape that minimizes molding energy. Molding energy refers to the average compliance generated by the deformation of the material. 【0018】 The input / output unit 30 may include a display device such as a screen and an input device such as a keyboard. The input / output unit 30 may also be a touch panel in which the display device and the input device are integrated. The input / output unit 30 is used for inputting design values ​​such as production conditions. 【0019】 The storage unit 20 includes non-volatile memory such as flash memory or an SSD (Solid State Drive). The storage unit 20 stores various programs for realizing the functions provided in the embodiment. In addition, a calculation formula 21 for calculating the intermediate shape is stored in the read / write area of ​​the storage unit 20. 【0020】 Furthermore, the memory unit 20 includes volatile memory such as RAM (Random Access Memory) and temporarily holds information when the processing unit 10 is operating. The processing unit 10 is a processor that controls the hardware of the intermediate shape calculation device 1. The processing unit 10 reads a program from the memory unit 20 into memory and executes it. In this way, the processing unit 10 realizes some or all of the above-mentioned functions for calculating the intermediate shape. 【0021】 The processing unit 10 includes an acquisition unit 11, a molding energy calculation unit 12, a displacement amount calculation unit 13, a determination unit 14, an intermediate shape calculation unit 15, an update unit 16, and a 3D data generation unit 17. The acquisition unit 11, molding energy calculation unit 12, displacement amount calculation unit 13, determination unit 14, intermediate shape calculation unit 15, and update unit 16 realize the shape calculation function, and the 3D data generation unit 17 realizes the 3D data generation function. 【0022】 The acquisition unit 11 acquires the design data for the initial shape of the forged product, the design data for the intermediate shape before modification, and the design data for the final shape. The forming energy calculation unit 12 uses the acquired design data to calculate the forming energy required to deform from the initial shape to the final shape. The displacement amount calculation unit 13 calculates the amount of shape displacement from the initial shape to the final shape. 【0023】 The determination unit 14 determines whether the objective function has converged based on whether the amount of change in the objective function, which is obtained from the molding energy and the amount of shape displacement, is less than or equal to a predetermined value. If the objective function has not converged, the intermediate shape calculation unit 15 calculates an intermediate shape that reduces the objective function. The update unit 16 sets the diffusion coefficient of the reaction-diffusion equation in the level set method at a desired part of the intermediate shape, and updates the pre-modification design data to the post-modification design data of the calculated intermediate shape based on the reaction-diffusion equation with the set diffusion coefficient. 【0024】 The 3D data generation unit 17 is 3D CAD software or the like, and draws a 3D model of the forged product. The 3D data generation unit 17 converts the design data of the intermediate shape generated by the shape calculation function into a point cloud indicated by the 3D coordinates included in the 3D point cloud data. The 3D data generation unit 17 generates 3D CAD data of the forged product by mapping the converted 3D coordinates to a 3D coordinate system. The generated 3D CAD data is output to the display device of the input / output unit 30 or the like. 【0025】 Each component of the intermediate shape calculation device 1 may be implemented with dedicated hardware. Alternatively, some or all of each component may be implemented by general-purpose or dedicated circuits, processors, etc., or combinations thereof. These may be comprised of a single chip or multiple chips connected via a bus. Some or all of each component may be implemented by a combination of the aforementioned circuits, etc., and programs. Furthermore, a CPU (Central Processing Unit), GPU (Graphics Processing Unit), FPGA (Field-Programmable Gate Array), quantum processor (quantum computer control chip), etc., can be used as the processor. 【0026】 Figure 2 is a flowchart illustrating the intermediate shape calculation method according to the embodiment. In the following explanation, in order to facilitate understanding of the technology, products with axially symmetric three-dimensional structures, such as drive pinions, will be used as examples. 【0027】 In step S11, the acquisition unit 11 sets the design data for the initial shape of the forged product, the initial design data for the first intermediate shape, the initial design data for the second intermediate shape, and the design data for the final shape. This design data can be set by acquiring it from, for example, a higher-level product design management system that performs product design. 【0028】 "Initial design data" refers to the design data initially provided to initiate the intermediate shape calculation process. In other words, initial design data is design data that shows the shape before it is modified by the intermediate shape calculation process performed by the intermediate shape calculation device 1. In this embodiment, the initial design data for the first intermediate shape is provided with design data of the same billet shape as the initial shape, and the initial design data for the second intermediate shape is provided with design data of the same shape as the final shape after the finishing process. However, this is not limited to this, and any shape may be set as the initial design data. 【0029】 Next, the molding energy calculation unit 12 calculates the molding energy from the initial shape to the final shape using the acquired design data (step S12). The molding energy calculation unit 12 calculates the surface force t in the three-dimensional shape Ω. i Considering the molding energy required for each step of the boundary ∂Ω defined in as the work done by the external force, the molding energy J from the initial shape to the final shape is calculated using the following equation (1). comp It is possible to calculate this. 【0030】 【number】 u i :Displacement field ε ij : Distortion σ ij :stress 【0031】 The molding energy calculation unit 12 can also calculate the molding energy for each process, as follows. In this case, the displacement between each shape is calculated first. Here, the linear elastic deformation of the three-dimensional shape Ω is expressed by the following equations (2) and (3) using the displacement field u. Equations (2) and (3) are also called the equation of state, the elastic equation, or the Navier-Cauchy equation. The displacement field u can be obtained by performing a numerical analysis of equations (1) and (2) using the finite element method. 【0032】 【number】 λ: Lame's first constant μ: Second constant of the glitter u: Displacement field 【0033】 【number】 u': Forced displacement on the boundary 【0034】 The forming energy calculation unit 12 then uses the calculated displacement to calculate the minimum forming energy that can be generated when the three-dimensional shape Ω is deformed. The forming energy calculation unit 12 calculates a first forming energy for deformation from the initial shape to an intermediate shape, and a second forming energy for deformation from the intermediate shape to the final shape. If the forging process includes multiple intermediate processes, the forming energy generated when deformation occurs from the initial shape to the shape after the first intermediate process is defined as the first forming energy, and the forming energy generated when deformation occurs from the shape after the last intermediate process to the final shape is defined as the second forming energy. 【0035】 In this embodiment, the molding energy calculation unit 12 calculates the molding energy generated when the material is transformed from the initial shape to the first intermediate shape, i.e., from the billet shape to the shape after the crushing process, as the first molding energy. Furthermore, the molding energy calculation unit 12 calculates the molding energy generated when the material is transformed from the second intermediate shape to the final shape, i.e., from the shape after the roughing process to the shape after the finishing process, as the second molding energy. In addition, the molding energy calculation unit 12 calculates the molding energy generated when the material is transformed from the first intermediate shape to the second intermediate shape as the third molding energy. 【0036】 The objective function of the molding energy J can be expressed by the following equation (4). Here, ε(u) = (∇u + ∇uT) / 2. The molding energy calculation unit 12 calculates the first molding energy, the second molding energy, and the third molding energy using the following equation (4). 【0037】 【number】 ε(u): Stress-strain field C: Elastic tensor 【0038】 The molding energy calculation unit 12 calculates the total molding energy generated when the shape changes from the initial shape to the final shape. In this embodiment, the molding energy calculation unit 12 calculates the total molding energy by integrating the calculated first molding energy, second molding energy, and third molding energy. If there is only one intermediate step, the molding energy calculation unit 12 calculates the total molding energy by integrating the first molding energy and the second molding energy. 【0039】 Next, the displacement calculation unit 13 uses equation (5) to calculate the shape displacement J from the initial shape to the final shape. disp Calculate (Step S13). 【number】 u: Displacement field The exponent p is used to emphasize areas with large displacements when calculating the amount of displacement. 【0040】 In step S14, the objective function is determined from the calculated molding energy and displacement. This objective function is the sum of the normalized values ​​of the molding energy and shape displacement. That is, the objective function J is expressed by the following equation (6). 【number】 Here, α is a predetermined constant that represents the weight set when calculating the objective function by adding the molding energy and displacement. 【0041】 In step S15, the determination unit 14 determines whether the objective function has converged based on whether the change in the objective function J obtained by equation (6) is less than or equal to a predetermined value. In this disclosure, the processes from steps S12 to S15 are also referred to as the "convergence determination process". Convergence of the change in the objective function J means the completion of the optimization of the intermediate shape. If the change in the objective function J is greater than the predetermined value, the determination unit 14 determines that the molding energy has not converged (S15, NO) and proceeds to step S16. If step S15 is the first time, the determination unit 14 determines that the molding energy has not converged (S15, NO) and proceeds to step S16. 【0042】 In step S16, the intermediate shape calculation unit 15 calculates an intermediate shape that reduces the objective function J. In this embodiment, the intermediate shape calculation unit 15 calculates the intermediate shape that reduces the objective function using a sensitivity calculation based on the adjoint variable method. For the sensitivity calculation, the shape derivative of equation (7) below, which is the design sensitivity of the objective function J, is used. The steepest descent method is used for the design sensitivity of the level set method. 【number】 n: Unit normal vector ∂θ: infinitesimal displacement vector 【0043】 In step S17, the update unit 16 updates the pre-modification design data to the calculated post-modification design data of the intermediate shape based on the shape derivative defined by the level set function. Specifically, the update unit 16 uses the calculated intermediate shape to set the diffusion coefficient of the reaction-diffusion equation in the method at a desired location of the intermediate shape, and calculates the post-modification design data of the intermediate shape from the reaction-diffusion equation of the set diffusion coefficient. The post-modification shape of the intermediate shape is calculated by the reaction-diffusion equation shown in the following equation (8). 【number】 φ: Level set function J': Shape derivative L: Representative length τ: diffusion coefficient K: Optimization parameter 【0044】 The constant K can be expressed, for example, as a stiffness matrix. Furthermore, the diffusion coefficient τ is defined as a region-dependent and directional tensor quantity, as shown in equation (9) below. In other words, the diffusion coefficient τ exhibits anisotropy in the desired region (e.g., the region to be flattened, the region to be prevented from overflowing the mold). This allows for the consideration of shape definition using the level set method. 【0045】 Figure 3 illustrates an example of shape definition using the level set method. In the left diagram of Figure 3, the shape definition using the level set method is not considered (i.e., the diffusion coefficient is a constant scalar value regardless of the location). In this case, the lower end of the optimized shape FR (workpiece axis end) is pointed downwards, as shown by the dashed line. Therefore, it is difficult to push the workpiece out of the mold with a pin (i.e., knock it out) at such a pointed lower end. In addition, in some cases, the area indicated by the dashed line may protrude from the mold during formation. 【0046】 Therefore, in the right-hand diagram of Figure 3, we consider the definition of shape using the level set method. The design space DS represents the space in which the shape F of the forged product can exist, and represents the mold. In the design space DS, the location where the shape exists is defined as "1", and the location where the shape does not exist is defined as "0". In the right-hand diagram of Figure 3, as shown by the dashed line, in the desired part of the intermediate shape to be formed in the flat section, the diffusion coefficient in the direction e2 in which diffusion is not desired (i.e., perpendicular to the direction e1 in which flattening is desired) is set to a value sufficiently larger than that perpendicular direction e1 (τ 22 >>τ 11)。It is possible to set a diffusion coefficient for a portion to be flattened via an input device such as a keyboard or a mouse. As a result, diffusion in the direction (e1) perpendicular to the direction (e2) in which flattening is desired is restricted, and diffusion in the direction in which flattening is desired is performed, enabling the formation of a flat portion. This flat portion can facilitate pushing out (i.e., knocking out) the workpiece from the mold with pins. Note that the flat portion shown in FIG. 3 is merely an example, and flat portions for knocking out can be arranged at at least one location and in various places on the forged product. 【0047】 Also, in the right diagram of FIG. 3, for a portion where it is desired to prevent the outer diameter of the shape from protruding from the mold, as indicated by the two-dot chain line, the diffusion coefficient in the direction e1 in which diffusion is not desired (i.e., the direction perpendicular to the outer edge (upper and lower) direction e2 of the mold) is set to a value sufficiently larger than that in its perpendicular direction (e2) (τ 11 >>τ 22 ). As a result, an intermediate shape can be formed such that the outer diameter of the shape does not protrude from the mold. 【Number】 ··· Equation (9) 【0048】 When the update unit 16 calculates the design data after the change of the intermediate shape in this way and updates the design data before the change to the design data after the change of the calculated intermediate shape, the process proceeds to step S12. The forming energy calculation unit 12 calculates the forming energy and the displacement amount using the design data after the change of the intermediate shape, and further executes a convergence determination process. The convergence determination process is repeatedly executed until the objective function J converges. 【0049】 In step S15, when the objective function J converges (step S15, YES), the process proceeds to step S18. In step S18, the intermediate shape when the objective function J converges is specified as the final intermediate shape. The three-dimensional data generation unit 17 converts the design data of each intermediate shape specified as the final intermediate shape into 3D CAD data (using arbitrary visualization software) and ends the process. 【0050】 The effect of intermediate shape calculation by the intermediate shape calculation device 1 will be explained using Figures 4 to 6. Here, α = 0.5 in equation (6) and p = 3 in equation (5) above. Figure 4 is a diagram illustrating the shape change of a forged product in the forging process. The upper part of Figure 4 shows the shape change of a product including the final intermediate shape obtained by the conventional technology (referred to as the "comparative example shape") as a comparative example. The lower part of Figure 4 shows the shape change of a product including the final intermediate shape obtained by the intermediate shape calculation device 1 of this disclosure (referred to as the "optimized shape"). 【0051】 The shapes of each product shown in Figure 4 are axially symmetric. Note that, for the sake of easier understanding of the technology, only one side of the cross-sectional shape relative to the central axis is shown in Figure 4, even though the cross-sectional shape is line-symmetric. 【0052】 As shown in Figure 4, shapes FR1 and F1 are given the same billet shape. Shapes FR4 and F4 are given the same final shape. Shapes FR2 and F2 are first intermediate shapes, and shapes FR3 and F3 are second intermediate shapes. As shown in Figure 4, the first and second intermediate shapes are different in the comparative example shape and the optimized shape. In the crushing process and roughening process, as described above, a flat portion is formed at the shaft end of the workpiece by setting the diffusion coefficient to have anisotropy in specific parts. That is, in the part where a flat portion is to be formed, the diffusion coefficient in the direction perpendicular to the direction to be flattened (e1) (e2) is set to a value that is sufficiently larger (for example, three orders of magnitude larger) than the value in the perpendicular direction (e1) (τ 22 >>τ 11 ). Furthermore, for parts where we want to prevent the outer edge of the shape from extending beyond the mold, the diffusion coefficient in the direction e1 (i.e., perpendicular to the direction e2 of the outer edge of the mold (up and down)) should be set to a value sufficiently larger than that in the perpendicular direction (e2) (τ 11 >>τ 22 ). 【0053】 Figure 5 illustrates the loads generated during the forging process when forming an optimized intermediate shape. Figure 6 illustrates the forming energy generated during the forging process when forming an optimized intermediate shape. In Figures 5 and 6, the shaded areas correspond to the optimized shape, and the hatched areas correspond to the comparative example shape. 【0054】 As shown in Figure 5, by changing from the comparative shape to the optimized shape, the load in the finishing process is reduced, resulting in a 10% reduction in the total load. Furthermore, as shown in Figure 6, the intermediate shape calculation device 1 according to this disclosure can reduce the forming energy related to the forging process by 23% by optimizing the intermediate shape. Therefore, this disclosure can contribute to reducing carbon dioxide emissions, achieving carbon neutrality, and realizing a decarbonized society by reducing energy consumption. 【0055】 As described above, the intermediate shape calculation device 1 of this embodiment can calculate the shape of an intermediate process without using a database containing data on forged products, and the configuration of the intermediate shape calculation device 1 can be simplified. 【0056】 Furthermore, according to the embodiment, in designing the intermediate shape of the forging process, the sum of the forging forming energy and displacement is used as the objective function, and the intermediate shape is derived by topology optimization calculation using the level set method. That is, in order to minimize the sum of the forming energy and displacement (which is approximately equal to friction energy), it is possible to design a process that places less load on the product and the mold. In other words, according to the embodiment, it is possible to design a process that can suppress forming defects such as scratches on the product and reduce mold wear. 【0057】 The intermediate shape includes a first intermediate shape, which is deformed from the initial shape, and a second intermediate shape, which is before being deformed into the final shape. In the first convergence determination process, the initial design data for the first intermediate shape is given design data with the same shape as the initial shape, and the initial design data for the second intermediate shape is given design data with the same shape as the final shape. Therefore, the initial design data for the convergence determination process can be easily set. 【0058】 Furthermore, according to this embodiment, the intermediate shape is calculated using a sensitivity calculation based on the adjoint variable method, where the objective function is the sum of the forging energy and the displacement. By using the adjoint variable method, calculations for each design variable can be omitted, thereby reducing computation costs. Moreover, according to this embodiment, a desired shape can be formed for a desired part by considering the shape definition using the level set method. 【0059】 It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. In the embodiments described above, an example was shown in which the forging process comprises two intermediate processes, a first intermediate process and a second intermediate process, but the forging process may comprise only one intermediate process having only one of these processes. Furthermore, in the above example, the intermediate shape was calculated using a sensitivity calculation based on the adjoint variable method, but the invention is not limited to this, and the intermediate shape may be calculated by a sensitivity calculation using, for example, the direct differential method or the difference approximation method. This disclosure can also be used as a program that causes a computer to execute the above-described intermediate shape calculation method, or as a non-temporary computer-readable medium storing the program. [Explanation of symbols] 【0060】 1. Intermediate shape calculation device 10 Processing Unit 11 Acquisition Department 12. Molding energy calculation unit 13 Displacement Amount Calculation Unit 14 Judgment section 15 Intermediate Shape Calculation Unit 16 Update section 17. 3D Data Generation Unit 20 Memory section 30 Input / output section

Claims

[Claim 1] An intermediate shape calculation device that repeatedly calculates design data representing the intermediate shape of a forged product and identifies design data representing the final intermediate shape, An acquisition unit that acquires design data for the initial shape of the forged product, design data for the intermediate shape before modification, and design data for the final shape, A molding energy calculation unit calculates the molding energy from the initial shape to the final shape using the acquired design data, A displacement calculation unit that calculates the amount of shape displacement from the initial shape to the final shape, A determination unit that determines whether the amount of change in the objective function, which is obtained from the molding energy and the amount of shape displacement, is less than or equal to a predetermined value, determines whether the objective function converges. If the objective function has not converged, an intermediate shape calculation unit calculates an intermediate shape that reduces the objective function, An update unit that sets the diffusion coefficient of the reaction-diffusion equation in the level-set method at a desired location of the intermediate shape, and updates the pre-modification design data to the calculated post-modification design data of the intermediate shape based on the reaction-diffusion equation with the set diffusion coefficient, Equipped with, Intermediate shape calculation device. [Claim 2] The intermediate shape calculation device according to claim 1, wherein the diffusion coefficient has anisotropy in a desired portion of the intermediate shape. [Claim 3] The diffusion coefficient in the direction perpendicular to the direction to be flattened is set to a value sufficiently larger than the diffusion coefficient in the direction to be flattened. The intermediate shape calculation device according to claim 1. [Claim 4] The diffusion coefficients in the direction perpendicular to the outer edge of the design space are set to be sufficiently larger than the diffusion coefficient in the direction perpendicular to the outer edge of the design space. The intermediate shape calculation device according to claim 1. [Claim 5] An intermediate shape calculation method that repeatedly calculates design data representing the intermediate shape of a forged product to identify design data representing the final intermediate shape, Computers The steps include obtaining design data for the initial shape of the forged product, design data for the intermediate shape before modification, and design data for the final shape. A step of calculating the molding energy from the initial shape to the final shape using the acquired design data, A step of calculating the amount of shape displacement from the initial shape to the final shape, A step of determining the convergence of the objective function based on whether the amount of change in the objective function, which is obtained from the molding energy and the amount of shape displacement, is less than or equal to a predetermined value, If the objective function has not converged, the steps include calculating an intermediate shape that reduces the objective function, The steps include setting the diffusion coefficient of the reaction-diffusion equation in the level set method, and updating the pre-modification design data to the post-modification design data of the calculated intermediate shape based on the reaction-diffusion equation with the set diffusion coefficient, Execute Intermediate shape calculation method.

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