• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.303-306
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• 1997

$\alpha$형과 $\beta$형 섬유조직의 압연 집합조직을 초기 집합조직으로 갖는 알루미늄 판재의 디프드로잉 공정시 집합조직 변화를 고찰하였다. 플랜지 변형 단계에서는 Bs성분은 감소하 였으며, Goss, Cu, P등의 성분들은 증가하였다. 컵의 윗쪽에서는 아랫쪽에 비하여 Goss, Cu 성분은 증가하고 P성분의 변화는 적었다. 이는 컵의 윗쪽에서는 플랜지에서 받은 평면변형 의 정도가 컵의 아랫쪽에 비하여 크기 때문이다. 실제 디프드로잉 공정에서의 변형량에서는 결정들이 안정방위로의 회전경로인 $\alpha$D형의 섬유와 $\beta$D형의 섬유로 이동하게 된다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.2936-2948
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• 1993

Multi-stage deep drawing is an important sheet metal forming process. The deformation mechanisms of sheet metals during forming processes are complicated mainly due to the geometry and the lubrication of tools involved, the formability and the anisotropic behaviour of the material. The multi-stage deep-drawing processes including normal-drawing, reverse-drawing, and re-drawing are analyzed by use of the rigid-plastic finite element method. The anisotropic behaviour represented by r-value can be incorporated into the formulation. Punch/die loads and thickness distributions were obtained as results of simulating axisymmetric deep drawing processes. The computed results showed good agreements with experiments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.886-900
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• 1989

The purpose of this paper is to obtain the effect of blankholding force in deep drawing process. Flange deformation is analysed by theoretical approach in order to apply the optimum blankholding force to the blank. As the result, the upper and lower blankholding force is determined in terms of variables in deep drawing process. Experiment are carried out with the high stiffness spring-type blankholder system. Theoretical upper blankholding force are relatively good agreement with experimental result and the range of initial blankholding forces for various materials tested are found by experiment.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.191-198
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• 1994

A practical example of the axisymmetric deep drawing process is simulated by the elastic-plastic finite element analysis using updated Lagrangian approach considering the large deformation. An approach is suggested to solve the problem of the ductile fracture that may encounter during the deep drawing process. The result can be applied to the design of the die for the axisymmetric deep drawing.

• Transactions of Materials Processing
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• v.3 no.4
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• pp.468-481
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• 1994

Mathematical description of arbitrarily-shaped tool surface are introduced by parametric patch approaches along with the related contact search algorithm. In order to maintain the advantages of membrane elements and to incoporate the bending effect, a BEAM(Bending Energy Augmented Membrane) element is proposed. Computation are carried out for some complex axisymmetric multi-stage deep drawing to verify the validity and the effectiveness of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.653-661
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• 2009

In order to reduce the noise and oscillation, it is consider a matter in all aspects about the noise stem from accumulator and the characteristic of transmission, Transformation of outside shape has change of noise occurrence at transmission process. Therefore, performed sound numerical analysis and conducted an experiment to examine the birthplace of accumulator's external shape change. In a sound numerical analysis, we can fond out transmission loss between inlet and outlet's sound pressure. In an experiment, we can make out transmission loss by sound wave separation theory through drawing sound pressure inlet and outlet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.66-70
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• 2008

In this study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. Tensile tests and limit dome height tests were rallied out at several temperatures between $25^{\circ}C$ and $300^{\circ}C$ to obtain the mechanical properties and forming limit diagram (FLD). The FLD-based criterion considering the strain-path and the blank temperature was used to predict the forming limit in a deep-drawing process of cross-shaped cup by finite element analysis. This criterion proved to be very useful in determining the optimal process conditions such as blank shape, punch velocity, minimum comer radius, fillet size, and so on, through the comparison between FEA and experimental data. In particular, the temperature of each tool that provided the best formability of the blank was determined by coupled temperature-deformation analyses. A practical method that can greatly reduce the forming time by increasing the punch speed during the forming process was suggested.

• Journal of Industrial Technology
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• v.19
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• pp.67-74
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• 1999

The mechanical properties including forming limit and deep-drawability of commercially-used sheet metals were experimentally estimated in this study. Uniaxial tensile test to obtain basic mechanical properties was carried out, followed by limiting dome height (LDH) test and forming limit diagram (FLD) test to quantitatively evaluate the sheet-formability. Deep drawing and reverse drawing tests were also performed to find out the critical values of the blank holding force and the gap between the die and the blank holder which enabled the deep drawing and reverse drawing of a successful cop without any wrinkle or fracture. The thickness of the cup wall along the rolling-, transeverse- and $45^{\circ}$-directions was measured and compared with one another. And the punch force-stroke curve and the critical punch force expected from the theory coincided with the experimental result very well for mild steel while not for aluminium alloy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.52-58
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• 2004

The material used is a commercial magnesium based alloy AZ31(Mg-3Al-1Zn)sheet with a thickness of 1.0mm. Uniaxial tension tests at warm temperature were carried out to investigate the material characteristics of K, m, and n. A warm drawing process with a local heating and cooling technique was developed to improve formability in this study with results of uniaxial tension tests because it is very difficult for Mg alloy to deform at room temperature by the conventional method. The die and blank holder were heated up, while the punch was water-cooled during deformation. FE simulations considering heat transfer were executed with Mg alloy to investigate the Improvement of deep drawability. For the assessment of improvement those were compare with the results of no considering heat transfer and room temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.938-942
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• 1996

Despite the increasing demand for improved product design, a limited number of works have been reported in the field of sheet metal forming. In the present study, introducing the Taguchi method, an optimal and robust combination of parameters is found and a data base management system and nomograms are utilized for knowledge acquisition. The developed system is applied to a deep drawing process, Through the present study, it is shown that the developed system is useful for the design and the formability estimation of sheet metal forming processes.