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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of Materials Processing
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Journal DOI :
The Korean Society for Technology of Plasticity
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Volume 1, Issue 2 - Dec 1992
Volume 1, Issue 1 - Sep 1992
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Physical Modeling Technique With Modeling Clay Of Metal Forming Processes
Im, Y.T. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 5~10
A Study on the Process Planning and Die Design of Hot Forging for Axisymmetric Parts(I)
Choi, J.C. ; Kim, B.M. ; Kim, S.W. ; Lee, J.S. ; Hong, S.S. ; Kim, N.H. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 20~32
This paper describes some research of Computer-Aided Process Planning and Die Design of Hot Forging for axisymmetric parts produced by the press. An approach to the system is based on knowledge based system. The system has been written in AutoLisp with personal computer. Knowledges for process planning & die design are extracted from the plasticity theories, handbooks, relevent references and empirical know-how of field experts in hot forging companies. The developed system is composed of five main modules, such as input module, process planning module, die design module, flow simulation module and output module which are used independently or in all. The final output is generated in graphic from. The developed system which aids designer provides powerful capabilities for process planning and die design of hot forging. This system also provides approximate flow pattern.
Finite Element Analysis of P/M Connecting Rod Forging
Park, Jong-Jin ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 33~41
Sintered P/M connecting rod is forged to increase density and to satisfy dimensional specifications. Flow of the materials is different form that of wrought materials due to pores in the preform. The Mises yield function was modified to. include the first invariant of stress tensor, and the associated flow rule was derived by applying the normality rule to the yield function. Axisymmetric and plane-strain finite element analyes were carried out for the ring and beam portions of the connecting rod, respectively. The flow of the preform and density change of the analysis are presented in this paper. A load-stroke curve was also presented by superimposing analysis results for the ring and beam portions.
Effects of Work-Hardening Exponent and Strain-Rate Hardening Exponent on the Determination of Friction Factor
Park, C.Y. ; Yang, D.Y. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 42~51
The ring compression test has been widely employed as an experimental means to determine the friction factor. The calibration curves are obtained by the rigid-plastic finite element analysis for various work-hardening exponent and strain-rate hardening exponent. The effects of work-hardening exponent and strain-rate hardening exponent are thoroughly studied and discussed from the finite element computation. The change of friction factor during height reduction in ring compression is also discussed. Then, the method to estimate the change of friction factor during ring compression is proposed.
A Simplified Three-Dimensional Finite Element Analysis of the Non-axisymmetric Extrusion Process
Shin, H.W. ; Kim, D.W. ; Kim, N. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 52~65
In this study a new simplified three-dimensional numerical method and the associated computer program have been developed to simulate the non-axisymmetric extrusion processes. The two-dimensional rigid-plastic finite element method under the generalized plane-strain condition is combined with the slab method. To define the die geometry for a non-axisymmetric extrusion. area mapping technique was used. Streamlined die surface was used to minimize the total extrusion pressure. Extrusion of square, hexagonal and 'T' section from round billet have been simulated and experimented with a model material. The computed results were in good agreement with the experiments in cross-sectional grid distortion. Computational results will be valuable for designing tool geometries and corresponding processes.
A Study on Central Bursting Defects in Forward Extrusion by the Finite Element Method
Kim, T.H. ; Lee, J.H. ; Kwon, H.H. ; Kim, B.M. ; Kang, B.S. ; Choi, J.C. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 66~74
According to the variation of hydrostatic pressure on the central axis of deformable material, the V-shaped central bursting defect may be created in extrusion or drawing processes. The process factors which affect the generation of defects are semi-angle of die, reduction ratio of cross-sectional area, friction factor, material properties and so on. The combination of these factors can determine the possibility of defect creation and the shape of various round holes which have been created inside already. By the rigid plastic finite element method, this paper describes the observations of change in shape of round holes with process conditions such as semi-angle of die, reduction ratio of cross-sectional area and friction factor at the non-steady state of axisymmetrical extrusion process when the round hole is already existed inside the original billet. Also, the effects of process factors are investigated to prevent the possible defects.
Measurement of Friction Coefficient in Stretching of Coated Steel Sheets
Kwon, Jae-Wook ; Kim, In-Soo ; Lee, Dong-Nyung ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 75~86
Coated sheet steels have been increasingly used in automotive industry for improving corrosion resistance. One of the arised concerns is frictional behavior of coated sheet steel in stamping process. But analyses of the frictional behavior are complex and difficult. A tensile strip test has been developed for evaluating friction under the condition which simulate the stretching of sheet. Tests are conducted under different die radius and lubrication conditions. Electro-galvanized steel sheets show a lower coefficient of friction than bare steel sheets whose coated layers have been chemically removed. The coefficients of friction are independent of die radius.
An Analysis of Superplastic Bulging of Sheet Metal
Hong, Sung-Suk ; Lee, Sung-Ho ; Lee, Jong-Sao ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 87~94
An analytical method has been presented for the study of the superplastic bulging process of sheet metal. Through this method, it is possible to obtain the optimum pressure-time curve for the superplastic forming and to predict the thickness distribution of bulged sheet metal with less computational cost than that by finite element analysis. Experiments have been performed to confirm the results of this analysis with Supral 150 sheets by adopting the computed optimum pressure-time curve. Good agreement between predictions and experimental data has been obtained for the bulged profile and its thickness distribution.
Plane Strain Analysis of Sheet Metal with Arbitrary Forming Conditions
Keum, Y.T. ; Lee, S.Y. ; Wagoner, R.H. ;
Transactions of Materials Processing, volume 1, issue 1, 1992, Pages 95~103
The plane strain analysis for simulating the stretch/draw forming operation with an arbitrarily-shaped tool profile is introduced. An implicit, incremental, updated Lagrangian formulation with a rigid-viscoplastic constitutive equation is employed. Contact and friction are considered through the mesh-normal, which compatibly describes arbitrary tool surfaces and FEM meshes without depending on the explicit spatial derivatives of tool surfaces. The linear line elements are used for depicting the formed sheet, based on membrane approximation. The FEM formulation is tested in the sections of automotive inner panel and two-side draw-in. Not only the excellent agreement between measured and computed strains is obtained in the stretched section, but also the numerical stability of formulation is verified in the draw-in section.