• 대한기계학회논문집A
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• 제32권7호
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• pp.610-616
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• 2008

For this study, the forming analyses and body strength tests of TBP were performed on the main pipe size 150A(KS D3507, KS D 3576 10S). The branched pipe sizes utilized were 25A, 32A, 40A, 50A, 65A, 80A, 100A and 125A. A general FEM program, ABAQUS, was used as the forming analyses method of TBP. Using the results, the strength of TBP was then tested in order to determine the safety of TBP when the working pressure was applied. The results indicate that TBP may be safely used in water-based fire protection pipe systems in terms of the strength.

• 소성∙가공
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• 제10권6호
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• pp.471-477
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• 2001

Milli-structure components are classified as a component group whose size is between macro and micro scales, that is, about smaller than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiments. Special containers or cases of cellular phone vibrator to save installation space are produced by rectangular-shaped drawing. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1142-1147
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• 2003

The formability of sheet metal appears better in incremental forming than in conventional forming. in this study, the effect of process parameters - tool type, tool size, feed rate, friction at the interface between tool and sheet, plane-anisotropy of sheet - on the formability was investigated by experiments and FEM analyses. it was found that the formability is improved when a ball tool of a particular size is used with a small feed rate and a little friction. Due to the plane anisotropy, the formability differs according to the direction of the tool movement. in this paper, details of the experimental procedures and the results obtained from the study are discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.471-476
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• 2001

Milli-structure components ate classified as a component group whose size is between macro and micro scales, that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiment. Generally, milli-structure containers or cases like cellular phone vibrator consist of rectangular-shaped drawing to save installation space. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

• 소성∙가공
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• 제6권4호
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• pp.279-290
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• 1997

The sectional forming analysis of stamping pocesses for aluminum alloy sheet metals was investigated. For the modeling of the anomalous behavior of aluminum alloy sheet. the Barlat's strain rate potential and Hill's 1990 non-quadratic yield theory with an isotropic hardening rule were employed. The rigid-viscoplastic FEM formulation which solves equilibrium equation for plane-strain stage with mesh-normal geometric constraints was derived. A new method to determine the Barlat's anisotropic coefficients was also suggested. To verify the validity of the formulation, the stretch and draw forming processes of a square cup were simulated.

• 소성∙가공
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• 제1권1호
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• pp.95-103
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• 1992

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.

• 한국해양공학회지
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• 제13권2호통권32호
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• pp.11-17
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• 1999

The objective of this paper is to introduce very fast but still stable solution using finite element procedures, and it has been used in an iterative mode for product design applications. A lot of numerical techniques have been developed to deal with the material, geometric and boundary condition non-linearities occurred in the stamping process. One of them, the One-Step FEM is very efficient and useful tool for a design and trouble-shooting in various stamping processes. In this method, the mathod, the material is assumed to deform directly from the initial flat blank to the final configuration without any intermediate steps. The formulation is based on the deformation theory of plasticity and the upper bound theorem. As a result of the calculations, the initial blank shape is obtained, together with the material flow, strains and thickness distribution in the part.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.333-336
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• 2008

There are many different kinds of forming processes to make a tubular product such as hydroforming and tube drawing. However, we should consider a better forming process in view point of energy consumption and $CO_2$ emission to save our earth. In this paper we have conducted FEM simulations to the various forming processes for sheet and tubular products to compare their energy consumptions. One example is tubular product and the other for drawn cup. From the comparisons of total energy for hydrofroming and tube sinking processes, hydroforming is consumed more energy than tube drawing. Also the cup drawing from sheet metal and tube sinking for the cup with flange indicate that the tube sinking is better than cup drawing of sheet metal in energy consumption.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.96-100
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• 2000

It is difficult to predict material behavior of forming process because the plastic instable flow phenomenon happens in practical forming process I. e. upsetting backward extrusion piercing indentation. In view of the direct relationship between instable material flow and quality defects of the products we should find out their phenomena, In this study we introduced the plastic spin and the kinematic hardening considering the kinematic hardening constitutive equation for rate-dependent material. Also analysis of upset forging is carried out using the rigid plastic FEM with Al7075

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.121-129
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• 1996

This study aimsdetecting defects for the forming precesses of X2 spline, which is designed by an industry expert. The exist process consists of 3 runs and 7 operations with 3 heat treatments. The rigid-plastic FEM analysis was carried out to design a new process and some defects were found. Thus the design was modified to get better results. it is ocnfirmed that the industry expert agree the possibility of defects derived from the FEM results.