• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1642-1650
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• 1995

Process design is one of the most important fields in metal forming, where the finite element method has appeared a useful method for industrial applications. In this study, a program using the rigid plastic finite element has been developed for process design in three-dimensional plastic deformation. The surface integration for calculation of the friction between die and workpiece has been implemented with care in numerical treatment. The developed program is applied to a precision coining process of electronic components. It is confirmed that the program developed here is suitable for process design in metal forming with three-dimensional plastic deformation.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.49-52
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• 1989

Some limits are in two-dimensional analysis by finite element method to electromagnetic machine having finite dimension. Therefore three-dimensional analysis by finite element method, which are modeling original form of models are needed in order to gain accurate solutions. This paper present three-dimensional time varing magnetic field analysis method using electric field E and magnetic scarlar potential $\Omega$, and examine sample model.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.3
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• pp.116-122
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• 2003

This paper proposes an efficient method for computing the 3-dimensional capacitance of complex structures. The proposed method Is based on Finite Element Method(FEM) and expands the conventional FEM by adopting variable division. This method improves the extraction efficiency 50 times when compared to the conventional FEM with equal division. The proposed method can be used efficiently to extract electrical parameters of on/off-chip interconnects in VLSI systems.

• Structural Engineering and Mechanics
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• v.51 no.4
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• pp.601-625
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• 2014

Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.317-322
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• 1989

Effective computational strategies have been proposed in the evaluation of stiffness matrices of rigid-plastic finite element method widely used in simulation of metal forming processes. The stiffness matrices are expressed as the sum of stiffness matrices evaluated by reduced integration and Liu's stabilization matrices which control the occurrence os zero-energy mode due to excessive reduced integration. The proposed method has been applied to the solution of fundamental 3-dimensional problems. The results clarified that the deformed mesh configuration was remarkably stabilized and computation speed attained about 3 times as fast as that of conventional 3-dimensional analyses. Furthermore, computation speed increases by a factor 60 when parallel computation is introduced. This speed has a tendency to increase as the total degree of freedom increases. As a result, this rigid-plastic finite element method enables us to analyze real 3-dimensional forming processes with practically acceptable computation time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.113-129
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• 2000

This study evaluates the behavior and strength of an anchorage zone of the prestressed concrete box girder bridge on the Kyungboo highway railroad using the 2D SUB-3D STM approach and a linear elastic finite element analysis. The 2D SUB-3D STM approach utilizes several two-dimensional sub strut-tie models that represent the compressive and tensile stress flows of each projected plane of the three-dimensional structural concrete in the selection of a three dimensional strut-tie model, evaluation of the effective strengths of the concrete struts, and verification of the geometric compatibility condition and bearing capacity of the critical nodal zones in the selected three-dimensional strut-tie model. The finite element analysis uses an 8-node brick element and the longitudinal prestressing force is considered as the equivalent nodal force. Analysis results show that the 2D SUB-3D STM approach and linear elastic finite element method can be effectively applied to the analysis and design of three-dimensional structural concrete including a prestressed concrete box girder anchorage zone.

• Advances in Computational Design
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• v.5 no.3
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• pp.277-289
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• 2020

This article describes the technology for constructing of a multiply-connected three-dimensional area's finite element representation. Representation of finite-element configuration of an area is described by a discrete set that consist of the number of nodes and elements of the finite-element grid, that are orderly set of nodes' coordinates and numbers of finite elements. Corresponding theorems are given, to prove the correctness of the solution method. The adequacy of multiply-connected area topology's finite element model is shown. The merging of subareas is based on the criterion of boundary nodes' coincidence by establishing a simple hierarchy of volumes, surfaces, lines and points. Renumbering nodes is carried out by the frontal method, where nodes located on the outer edges of the structure are used as the initial front.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.9
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• pp.1539-1545
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• 2003

A lot of researches have been performed on the equal channel angular pressing (ECAP) which produces ultra-fine grains. Along with the experiments, the finite element method has been widely employed to investigate the deformation behavior of specimen during ECAP and the effects of process parameters of ECAP. In this paper, pure-Zirconium is considered for ECAP process by using three-dimensional finite element analysis. The results have been compared with those of previous two-dimensional analysis and with the experimental results

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.117-124
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• 1993

The Neumann Expansion method has been used for evaluating the response variability of three dimensional truss structure resulting from the spatial variability of material properties with the aid of the finite element method, and in conjunction with the direct Monte Carlo simulation methods. The spatial variabilites are modeled as three-dimensional stochastic field. Yamazaki 〔1〕 has extended the Neumann Expansion method to the plane-strain problem to obtain the response variability of 2 dimensional stochastic systems. This paper presents the extension of the Neumann Expansion method to 3 dimensional stochastic systems. The results by the NEM are compared with those by the deterministic finite element analysis and by the direct Monte Carlo simulation method

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.1
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• pp.16-22
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• 2001

In this study for reduction degree of freedom of dynamic model, a mixed method to combined finite element method and transfer matrix method is presented. This offers the advantages of an automatic reduction in the size of the eigenvalues problem and of a straightforward means of dynamic substructuring. The analytical procedure in this method for dynamic analysis of 3-dimensional cantilevered box beam are described. the result of numerical example is shown to demonstate the efficiency and accuracy of this method. The result form this example agree well those obtained by ANSYS, By using this technique, the number of nodes required in the regular finite element method is reduced and therefore a smaller com-puter can be used.