• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.297-300
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• 2009

The roll forming process is often used to manufacture long, thin-walled products such as a pipe. The final cross-section is a comparatively simple open-channel, a closed tube section or a complex profile with several bends. In recent years, that process is often applied to the bumper beam in the automotive industries. In this study, a optimal Center Floor Cross Member manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle, and also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.293-296
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• 2009

In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal front side member manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.50-53
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• 2001

Hydroforming process has become an effective manufacturing process because it can be adaptable to forming of complex structural components. Tube hydroforming has been successfully developed in the real industrial field by many researchers. However, there still remains the constraint about shape which can be manufactured by tube hydroforming. In order to improve this constraint of shape and formability of conventional sheet metal forming, hydroforming process of sheet metal pairs becomes an important technology. In the present work, the finite element analysis of hydroforming process of sheet metal pairs is presented. After basic study about experimental parameters based on numerical analysis, hydroforming process of sheet metal pairs is developed which uses hydraulic pressure as a main forming source.

• Transactions of Materials Processing
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• v.16 no.2 s.92
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• pp.144-149
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• 2007

The superplastic forming/diffusion bonding(SPF/DB) is widely used in the automotive and aerospace industry because it has great advantage to produce complex, light and strong parts. But the superplastic forming process requires much forming time and generates excessive thinning in the thickness distribution of formed part. It is necessary to minimize trial and error for SPF/DB Process. Finite element analysis using $L_{18}$ orthogonal may table of Taguchi method for 3-Sheet D/B process is carried out. Through the study, effect of process parameters, such as DH region size, thickness and friction coefficient, is evaluated and the optimum condition is derived.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.128-133
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• 2004

This study has been focused on the development of shear forming process of grid for lead-acid battery. The grid plays an important role in the flow of electricity because the grid is a skeleton of the pasted plate. Therefore, it must be of the highest quality to prevent plate failures and then, battery failure, and ensure the best battery performance possible. The finite element analysis of the shear forming process is carried out and the result is compared with the experimental data. The influence of the numerical parameters such as clearance, velocity of punch and critical damage value on the simulation results turns out to be very considerable.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.379-388
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• 2000

This study aims to examine the influence of experimental and numerical factors on the results of the test and finite element simulation to evaluate the formability of sheet metals. The stretch-forming test with a hemispherical punch is carried out to obtain the limiting dome height (LDH) and forming limit diagram (FLD) for several kinds of aluminium and steel sheet. The results of the LDH and FLD tests are analysed to find any correlation with the uniaxial tensile properties. It proves that the size of the prescribed grid has great influence on the measured value of strain. The finite element analysis of the punch stretching process is also carried out and the result is compared with the experimental data. The influence of the numerical parameters such as friction coefficient, element size and anisotropy model on the simulation results tms out to be very considerable.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.25-36
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• 1994

The sheet metal forming process is one of the most important manufacturing processes in the modern industry. From the view point of mechanics involved, it is very difficult to predict whether a newly designed sheet metal part can be formed without defects such as fracture, wrinkling and surface unevenness, etc. In order to reduce the effort taken in the trial-and-error process and to control the process effectively, a systematic method for process modeling is to required. The aim of sheet forming simulation through the process modeling is to reduce the lead time for die disign and manufacture by process modeling is to reduce the lead time for die design and manufacture by means of investigating the deformation mechanics and the mutual interaction between the process parameters. In this paper, the necessity, the present status, and the future technology about CAE of sheet forming simulation have been discussed.

• Transactions of Materials Processing
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• v.13 no.8
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• pp.696-703
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• 2004

The purpose of this study is to examine the bulk/sheet forming characteristics of bulk amorphous alloys in the super cooled liquid state. Recently it is reported that amorphous alloys exhibit stress overshoot/undershoot and non-Newtonian behaviors even in the super cooled liquid state. The stress-strain curves with the temperature-dependences as well as strain-rate dependence of Newtonian/non-Newtonian viscosities of amorphous alloys are obtained based on the previous experimental works. Then, those curves are directly used in the thermo-mechanical finite element analyses. Upsetting and deep drawing of amorphous alloys are simulated to examine the effects of process parameters such as friction coefficient, forming speed and temperature. It could be concluded that the superior formability of an amorphous alloy can be obtained by taking the proper forming conditions.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.49-57
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• 2010

A forming limit diagram (FLD) defines the extent to which specific sheet material can be deformed by drawing, stretching or any combination of those two. To determine the forming limit curve (FLC) accurately, it is necessary to perform the tests under well-organized conditions. In this study, the influence of several geometric or process parameters such as the blank shape and dimensions, strain measuring equipments, test termination time, forming speed and lubricants on the FLC is investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.531-534
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• 2008

A new forming process of the large-size forging within the limit of forming loads is developed by introducing the drawing process, which usually used to apply to sheet forming. For the development of the forming process, corresponding numerical simulation are carried out. The approach is based on the Taguchi method, and utilize the DOE for design of FEM analyses. In this study, the important factors are chosen at first, and then the concept of signal-to-nose(S/N) rate is applied to evaluate the formability of large size forging-products, and each value of the design parameter is determined.