• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.86-93
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• 2013

Main function of the Press forming Machine is the forming for plates. The head of the Press forming machine consist of several parts. It was named Press forming-contraction and Press forming_expansion according to formability of plates. Aluminium and Titanum plates are forming by using the Press forming machine. In this study, we analyzed sheet metal forming including plastic deformation and the contact pressure in the bearing. Finite element analysis results of Press forming-contraction and Press forming_expansion show the similar results of the actual specimen plates and the bearing contact pressures show the acceptable level of stress in both aluminum and titanium specimens.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1000-1009
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• 2008

Hydro-mechanical forming process has numerous advantages compared to those of a conventional deep drawing process such as an excellent surface quality and low costs of dies. In fact, Hydro-mechanical forming is a desirable forming process for producing complex parts in automotive body components, and it is an excellent candidate for the forming process of aluminum panels. In this research, Hydro-mechanical forming process with a cross shape punch has been studied for Al-Si-Mg alloy sheets. Finite element analysis by LS-Dyna has predicted the deep drawing depth of the aluminum sheets, and the experiment has confirmed that result. Put Abstract text here.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.7
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• pp.1107-1118
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• 2001

The forming limit diagram introduced by Keeler and Goodwin has been used generally to analyze the formability of sheet metal. However, path dependent forming limit curves based on the state of strain can be explained only by a single criterion which is based on the state. In this study, experimental forming limits in strain space of some metal sheets are transformed into forming limit curves in stress space. Effects of yield criterion are investigated in transforming the forming limit curves. Some important design aspects which are based on the close prediction of movements in forming limit curves during sheet forming are concluded.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.4
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• pp.44-49
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• 2014

Roll forming technology has a problem in that it depends only on experience without accurate data in the actual field. To solve this problem, it is necessary to procure accurate data during the roll forming process. To this end, we determined the operating force and the material thickness by implementing several changes to those variables during an experiment. This study compares the FEA results and experimental results. Experimental results were used for the basic data of the design. The FEA results show that the roll forming machine is operating accurately and safely. And, a comparison of the results shows that the design of the automatic roll forming machine is operating in the right way. This design of an automatic roll forming machine will be helpful for many areas of the industry.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.293-295
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• 2007

The thixoforming process become important for forming automobile parts. But, the thixoforming process cannot still prevent to forming defects such as pores and shrinkage which reduce mechanical properties of automobile parts. Therefore, it is necessary to analyze the correlation between forming defects and mechanical properties. However, it is difficult to get data about relations between mechanical properties and forming defects in thixoformed aluminum alloy parts. In this study, three parts of aluminum thixoformed knuckle have been analyzed using tensile test and computer tomography(CT scan). Experimental results showed that the elongation properties of thixoformed aluminum parts were significantly dependent on size and number of forming defects.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.840-844
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• 2012

Roll forming process is a sheet metal forming process where the forming occurs with rolls in several steps, often from an undeformed sheet to a product ready to use. And each pair of forming rolls installed in a forming machine operates a particular role in making up the required final cross-section. This process used to many industry manufactures and recently apply to automotive industry. This study, FEM simulation applied bumper reinforcement using SHAPE-RF software and analyzed about total effective strain, longitudinal strain, thickness according to the roll-pass.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.375-378
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• 2009

Hot press forming is a new forming process which also names as hot stamping. It can greatly enhance the formability of forming parts. This paper researches the formability of boron steel sheet in hot bending process which is a kind of hot press forming. In the text, the influence of hot press forming processing parameters, such as the heating temperature, blank holding force, punch speed and punch and die radius, on the mechanics properties and microstructure of the hot bending parts was analyzed by tension test and the metallographic observation on the parts with various processing parameters. The relationship between blank holding force and punch load was also presented.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.4
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• pp.247-255
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• 2016

Sheet metal-forming processes such as stamping, deep drawing, bending, shearing, hydroforming, hydromechanical deep drawing, rubber forming, and incremental forming have been widely used in the automotive, aircraft, and ship-building industries. With the expansion of the automotive industry, research on these processes has been remarkably developed in Korea since the 1980s. Here, we review the history of this research as well as recent trends in sheet metal-forming processes. This overview focuses specifically on the results of research in Korea and on the works of Professor D.Y. Yang, in honor of his retirement.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.210-216
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• 2001

This paper presents an analytical study that can predict the path-dependent forming limit of anisotropic sheet materials that experience various combinations of strain paths. To predict the forming limit diagrams(FLD), the proposed analytical procedure is performed within the framework of the Marciniak and Kuczynski(M-K) approach by using the Barlat and Lians non-quadratic anisotropic yield criterion and introducing the effect of the existence of a strain gradient over a stretching punch. The predicted path-dependent forming limit of an anisotropic sheet has been compared with the published experimental results. It has been found that the predicted path-dependent forming limits are in good agreement with the experimental data.

• Transactions of Materials Processing
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• v.18 no.3
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• pp.236-244
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• 2009

In response to growing environmental and collision-safety concerns, the automotive industry has gradually used high-strength and ultla-high-strength steels to reduce the weight of automobiles. In order to overcome inherent process disadvantages of these materials such as poor formability and high springback at room temperature, hot forming has recently been developed and adopted to produce some important structural parts in automobiles. This method enables manufacturing of components with complex geometric shapes with minimal springback. In addition, a quenching process may enhance the material strength by more than two times. This paper investigates mechanical and forming characteristics of high-strength boron-alloyed steel with hot forming, in terms of hardness, microstructure, residual stress, and springback. In order to compare with experimental results, a finite element analysis of hot forming process coupled with phase transformation and heat transfer was carried out using DEFORM-3D V6.1 and also, to predict high temperature mechanical properties and flow curves for different phases, a material properties modeler, JMatPro was used.