• 소성∙가공
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• 제9권5호
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• pp.469-477
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• 2000

Most of researches have been performed on the formability of axisymmetric shape, but it is insufficient that the study on Process variables of elliptical deep drawing Product. There are many Process variables exerted influence on the formability of products. Particularly, blank shape is more important than the others in elliptical deep drawing process. In this study, blanks of three types were proposed and compared using thickness distribution and movement of sheet during the process. The aim of a paper is to obtain optimal blank shape through experiment and finite element analysis(FEA).

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.48-52
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• 2006

The drawability of AZ31B magnesium sheet is estimated at various temperatures (200, 250, 300, 350 and $400^{\circ}C$), and forming speed (20, 50, 100 mm/min), thickness (0.5, 0.8, 1.0, 1.4 mm). The deep drawing process of circular cup and square cup were used in forming experiments. Experimental and FEM analysis are performed to investigate drawability and affection of controlled blank holding force. Through the controlled blank holding force, drawability was improved. This result is verified by FEM analysis. Through the observation of microstructure, the main cause is investigated as a quantity of the dynamic recrystallization.

• 소성∙가공
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• 제16권5호통권95호
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• pp.401-405
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• 2007

Due to the low densities and high specific strength and stiffness, magnesium alloy sheets are very attractive lightweight materials for automotive and electrical products. However, the magnesium alloy sheets should be usually formed at elevated temperature because of their poor formability at room temperature. For the use of the magnesium alloy sheets for an industrial, their mechanical properties at elevated temperature and appropriate forming process conditions have to be developed. In this study, non-isothermal simulation of a square cup drawing of magnesium alloy sheets have been conducted to evaluate a proper forming process conditions such as the tool temperature, the tool shoulder radius, friction between the blank and the tools. According to this study, appropriate forming process conditions of square cup drawing at elevated temperature from magnesium alloy sheets are suggested.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.237-241
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• 1998

This study is concerned with the optimum blank design which is able to minimize earing phenomena. A new analytic method is proposed to determine the optimum blank shape only using the tension test and standard deep drawing tests. Introducing a dimensionless parameter related to the earing and using a Fourier analysis, the optimum blank shape can be obtained by R-value and the tested results. The theoretical results by the proposed method are good agreement with the experimental results through several deep drawing tests using steel as working materials.

• 소성∙가공
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• 제7권6호
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• pp.594-602
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• 1998

The design analysis of axisymmetric, multi-stage deep drawing dies was performed using the rigid-viscoplastic finite element formulation. In the formulation the axisymmetric CFS algorithm was employed. Hill's non-quadratic normal anisotropic yield criterion and isotropic hardening rule were considered. For trial initial displacements and tool contact points. the geometric force equilibrium method was adopted. In order to see the validity of the formulation, the multi-stage deep drawing processes of shell-cylinder front part of hydraulic booster were simulated. The simulation showed good agreements with measurments and PAM-STAMP results.

• International Journal of Precision Engineering and Manufacturing
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• 제6권4호
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• pp.31-36
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• 2005

This paper describes a research work on the die design for the deep drawing & ironing(D. D. I) of high pressure gas cylinder. D. D. I die set is large-sized die used in horizontal press, which is usually composed of a drawing, and an ironing die. Design method of D. D. I die set is very different from that of conventional cold forging die set. Outer diameter of the die set is fixed because of press specification and that of the insert should be as small as possible for saving material cost. In this study, D. D. I die set has been designed to consider those characteristics, and the feasibility of the designed die has been verified by FE-analysis. In addition, the automated system of die design has been developed in AutoCAD R14 by formulating the applied methods to the regular rules.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.21-25
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• 2000

An inverse finite element approach is employed for more capability to design the optimum blank shape from the desired final shape with small amount of expense and computation time For multi-stage sheet metal forming processes numerical analysis is expense difficult to carry out the to its complexities and convergence problem. It also requires lots of computation time. For the analysis of elliptic cup with large aspect ratio intermediate sliding constraint surfaces are difficult to describe. in this paper multi-stage finite element inverse analysis is applied to multi-stage elliptic cup drawing processes to calculate intermediate blank shapes and strain distributions in each stages. To describe intermediate sliding constraint surfaces an analytic scheme is introduced to deal with merged-arc type sliding surfaces.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.417-418
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• 2012

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.471-474
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• 2007

On the road, geometric structure such as horizontal alignment, vortical alignment and crossing inclination ate important to explain characteristics of road and safety analysis. Especially, horizontal and vortical alignment are have to do with safety of covering. In existing road, for the safety analysis or alignment improvement and expansion pavement, it needs alignment factor of road. Alignment factor of road can be acquired by design drawing. But, design drawing can be not exist because of rack of facility management and national policy that centered to construction. And also, existing design drawing have a lot of differences in comparison with another existing design drawing cause of alignment improvement. In this case, for the precise analysis of alignment, 3-dimensional location information on the road centerline and acquisition of location information which related geometric structure are must to be preceded. In this study, therefore, it provide alignment factors which needed to alignment improvement and road safety analysis by acquisition of road space information and extraction of road centerline data using LiDAR data.

• 대한기계학회논문집B
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• 제30권7호
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• pp.612-621
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• 2006

Drawing is a mechanical operation attenuating material thickness to an appropriate level for the next processing or end usage. When the input material has a form of bundle or bundles made of very thin and long shaped wires or fibers, this attenuation operation is called 'bundle drawing' or 'drafting'. Bundle drawing is being used widely in manufacturing micro sized wires or staple yarns. However, the bundle processed by this operation has more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical laws containing physical variables, i.e. linear density and velocity as the dynamic state variables of the bundle fluid. The governing equations resulting from the modeling show that they appear in a slightly different form from what they do in a continuum fluid. Then, the governing equations system is simplified in a steady state and the bundle dynamics is simulated, showing that the shape of the velocity profiles depends on two model parameters. Experiments confirm that the model parameters are to be well adjusted to show a coincidence with the theoretical analysis. The higher the drawing ratio and drawing speed we, the more sensitive becomes the bundle flow to exogenous disturbances.