The NUMISHEET conference series is the most influential international conference in the field of Numerical simulation of sheet metal forming processes ( numerical analysis of sheet metal forming processes), and the most prominent experts in the field of numerical analysis of sheet metal forming processes gather to exchange ideas and discuss technologies related to sheet metal forming processes.

Hello. This is Yoon Ki-hoon, manager of the Kia plastic surgery department. I gave a presentation in a session on the subject of Multiscale modeling of deformation, and about 30 to 40 numerical analysis researchers from domestic and foreign universities and corporate managers watched with interest. Then, we will introduce the contents of the presentation.

[The purpose of research]

Figure 1. Springback prediction process through interlocking analysis of forming structure

Recently, consumers' car preferences are rapidly changing, and plans to produce various car models are accelerating. For this reason, most automotive engineers are constantly being asked to develop new technologies that can reduce the time it takes to develop and customize new models, and they want to introduce concurrent engineering engineering into the new model development process .

Mold engineers are similarly attempting to reduce mold development time by eliminating additional calibration man-hours. Structural analysis usually considers the mold as a rigid body to simplify engineering challenges. However, in reality, the panel forming force causes contact pressure on the mold shape surface, and the pressure causes elastic deformation of the mold.

Fig. 2. Mold model with elastic deformation

This is a major barrier for mold engineers to predict mold deformability. This mold deformation necessitates additional springback analysis and manual work after metalworking. To shorten this additional process, it is necessary to accurately predict where and how much the mold will deform . Through the analysis shown in Figure 1, an accurate compensation amount must be calculated and reflected in the mold design stage.

Previous studies have proposed various approaches to predict warpage and demonstrated the effectiveness of coupled analysis of molded structures. Molding structure integrated simulation was performed to reduce mold manufacturing cost and increase productivity. By linking structural analysis with molding analysis, springback for fender panels could be accurately predicted.

Figure 3. Structural analysis model of mold using midas MeshFree of IBM technique

[Conclusion and future plans]

In this study, the form-structure coupling analysis was applied to the press mold, and the mold deformation distribution was obtained as the final analysis result. The results of this analysis were found to be similar to the values ​​measured in the actual mold .

Figure 4. Results of mold deformation analysis using MeshFree-1

Figure 5. Results of mold deformation analysis using MeshFree-2

Figure 6. Results of mold deformation analysis using MeshFree-3

Additionally, we were able to prove that the presented mold deformation analysis methodology resulted in a significant reduction in the required time , and we were able to establish a process capable of simultaneously performing mold design and deformation analysis.

Figure 7. Mold deformation analysis time of the improved process compared to the existing process

The improved process can be put to practical use in mold design practice without specific expertise in FEM. In particular, it seems to be a cost-effective method for mold makers who need fast and accurate analysis but find it difficult to hire analysis experts . We plan to apply this analysis process to all molds developed in the future.

Many researchers and engineers who attended the presentation session asked questions about midas MeshFree. We will introduce the questions we received here.

Q. Can MeshFree be used for hot stamping molds?

A. Analysis considering thermal factors can also be used without problems.

Meshfree

capable of structural analysis

as well as heat transfer and thermal stress analysis

Q. Can anisotropic materials be considered in MeshFree?

A. Anisotropic materials can be considered. However, it was not taken into account in our analysis.

     This is because the properties of anisotropic materials in mold design are negligible.

Meshfree,

which can examine the deformation of various materials,

including orthotropic, superelastic, and elastomeric

Q. Which company made MeshFree? Is this an internal KIA development?

A. It is not an internal development of KIA.

     It was created by Midas IT, a company specializing in Simulation S/W development and distribution in Korea.

MIDASIT directly develops

and distributes engineering software

for technological independence in Korea

[Presentation impressions]

Due to the fact that meshing is not considered in depth, academics generally doubt the reliability of IBM's technique (Implicit Boundary Methods). In my presentation, I emphasized that 'there is no problem if you get results that are fast, easy, and similar to FEM in the field'. Of course, the academic approach pursued by the academic world is important, but in the field, it is very important to quickly obtain analysis results for the real thing.

Fast and Easy

Analysis results similar to FEM