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장성호;서대교
- Transactions of Materials Processing
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- v.11 no.5
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- pp.423-429
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- 2002
The limiting drawing ratio (LDR) under uniform heating of blanks was measured at the various temperature ranges between 25 and 25$0^{\circ}C$ by using two different blank shapes, square and circular blanks, and six different blank sizes with the drawing ratios(DR) of 2.4 to 2.9. The galvannealed steel sheet (SCP3CM 60/60) of 0.7mm thickness were used. The LDR at warm forming condition reached 1.2 times of that at room temperature, and the maximum drawing depth reached 1.9 times. The higher temperature was adopted, the more stable and uniform thickness strain distribution was observed. Some cases of the experimental results were compared with the analitical results using the commercial finite element method (FEM) code.
https://doi.org/10.5228/KSPP.2002.11.5.423 인용 PDF KSCI

이종국;강명순
- Journal of the korean Society of Automotive Engineers
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- v.11 no.4
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- pp.35-42
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- 1989
The major purpose of this paper is a study on the effect of die profile radius on the formability of spring-type blankholder system in deep drawing process. By drawing the various materials, formability is studied by means of checking the drawing force, blankholding force variation, limiting drawing ratio and wall wrinkling phenomenon. As the die profile radius increases, the maximum drawing force and maximum blankholding force decrease regardless of lubrication condition. Because better lubrication induces blankholding force to rise, spring type blankholder system is better to protect flange wrinkling phenomenon than constant pressure type. And wall wrinkling phenomenon was not detected in experimental die radius range, so the Miyakawa's upper wrinkling limit is understimated in case of material tested.
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- Proceedings of the Korean Society for Technology of Plasticity Conference
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- 1998.06a
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- pp.74-82
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- 1998
The limit drawing ratio (LDR) is a major process parameter in the process design of deep drawing. If the actual drawing ratio is greater than the LDR for a particular stage, then an intermediate stage has to be added to the process sequence to avoid failure during the ratio. In this study, the optimal process design considering forming limit is performed for the first-drawing and redrawing by using finite element method combined with ductile fracture criterion. The LDR and the site of fracture initiation are predicted by means of the fracture criterion. From the results of finite element analysis, the optimal value of drawing ratio is obtained, which contributes to the more uniform distribution of thickness and the smaller values of the ductile fracture in final cup.

Song, Y.S.;Kim, B.J.;Han, S.H.;Chin, K.G.;Choi, S.H.
- Transactions of Materials Processing
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- v.17 no.7
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- pp.517-522
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- 2008
A visco-plastic self-consistent (VPSC) polycrystal model has been applied to simulate texture simulation and anisotropic properties of DP steels during deep drawing process. In order to evaluate the strain path during deep drawing, a steady state was assumed in the flange part of deep drawn cup. The final stable orientations were strongly dependent on the initial location in the blank. The evolution of anisotropy of DP steel sheets has been demonstrated through comparison of plastic strain rate vector at the different plastic strain levels.
https://doi.org/10.5228/KSPP.2008.17.7.517 인용 PDF KSCI

Song, Y.S.;Kim, B.J.;Han, S.H.;Chin, K.G.;Choi, S.H.
- Proceedings of the Korean Society for Technology of Plasticity Conference
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- 2008.05a
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- pp.396-399
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- 2008
A visco-plastic self-consistent (VPSC) polycrystal model has been applied to simulate texture simulation and anisotropic properties of DP steels during deep drawing process. In order to evaluate the strain path during deep drawing, a steady state was assumed in the flange part of deep drawn cup. The final stable orientations were strongly dependent on the initial location in the blank. The evolution of anisotropy of DP steel sheets has been demonstrated through comparison of plastic strain rate vector at the different plastic strain levels.
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