• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.324-327
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• 1995

In this research, FEM solution to analysis near field of high Tc superconductor microstrip antenna is presented. This method uses the interpolation function with vector edge triangular element. The advantage of this element is elimination of spurious solutions which are attributed to the lack of enforcement of the divergence condition. The solutions of this method will be used to have a good fundamental data for next reaserch about analysis of HTS microstrip array antenna etc.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.355-361
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• 2004

The finite element method were used to determine the stress intensity factor of cracked plate. The stress method, displacement method and J Integral are most popular finte element method. ANSYS proposed another a kind of displacement method. In this paper, it was examined that the accuracy and utility of the ANSYS method could believable to determine the stress intensity factors of centered inclined crack. Generally, inclined crack has two portion of stress intensity factors, tensile mode F1 and shear mode F2. For the purpose of increasing the accuracy of stress intensity factors, examined the effect of the numbers of nodes and elements, crack tip element size and number of partition of the crack tip vicinity. It was found that the method proposed by ANSYS is useful and has high accuracy. Accuracy of calculated stress intensity factors was increased by increase of the number of nodes and elements, and at the small size of crack tip elements can get more highly accuracy.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.220-222
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• 1999

This paper presents a numerical analysis of the eddy current testing with cracked pipe using finite element method (FEM). ${\vec{A}},\;{\phi}-{\vec{A}}$ method is adopted for the formulation of 3-dimensional(3-D) FEM with the brick element. The cracks investigated here are the inner and outer surface of axial symmetry, 90 degree circular one. The algorithm of 3-D numerical analysis is employed for the axisymmetric pipe with the cracks. In order to verify the validity of 3-D numerical analysis, the results are compared with those of 2-D analysis with the same type of the model. The differential impedance is obtained by using energy method and its locus are various 8-shaped curves for each cracks. The ICCG method is used for the calculation of a matrix.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.6
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• pp.829-836
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• 2001

A dependable boundary reconstruction technique is proposed. The finite element method is used for the analysis of the direct heat conduction problem to realize the deformable grid system. An appropriate strategy for grid update is suggested. A complete sensitivity analysis is performed to obtain the derivatives required for restoration of the optimal boundary. With the result of the sensitivity analysis, the unknown boundary is sought using the sequential quadratic programming. The method is applied to reconstruction of boundaries with sinusoidal, step, and cavity form. The overall performance of the proposed method is examined by comparison between the estimated the exact boundaries.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.11-22
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• 1989

The finite element utilizing isoparametric plate element is applied for the elastic analysis of straight box girder bridges. A continuous box girder is analyzed as an example to verify the validity and accuracy of this method. It is indicated that the deflections and longitudinal stresses obtained by this method agree well with those from the orther methods. This theory may, therefore, be directly used as an efficient tool to analyze and design box girder bridges subjected to arbitrary loading and boundary conditions.

• Progress in Superconductivity
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• v.3 no.2
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• pp.183-187
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• 2002

In this paper we analyzed the electromagnetic behavior of high $-T_{c}$ superconductor under the quench state using finite element method. Poisson equation was used in finite element analysis as a governing equation and was solved using algebra equation using Gallerkin method. We first investigate d the electromagnetic behavior of U-type superconductor. Finally we applied our analysis techniques to 5.5 kVA meander-line superconducting fault current limiters (SFCL) which are currently developed by many power-system researcher in the world. Meshes of 14,600 elements were used in analysis of this SFCL. Analysis results show that the distribution of current density was concentrated to inner curvature in meander-line type-superconductors and maximum current density 14.61 $A/\m^2$ and also maximum Joule heat was 6,420 W/㎥. We concluded that this meander line-type SFCL was not pertinet fur uniform electromagnetic field distribution.n.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.1
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• pp.114-119
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• 2002

Cochlea is well known to have the ability to analyze a wide frequency and this ability seems to be caused to the Basilar Membrane(BM) configuration. However, the relationship between the Cochlea frequency-position map is not clear. In this paper, the three-dimensional BM Model was made using the Finite Element Method. Then an attempt was made to examine the influence of the BM configuration on the Cochlea frequency-position map. Theoretical consideration reveals that the wide frequency-position of Cochlea is achieved by not only the BM configuration change along the length of the Coohlea but also the change of the Young's module of the BM along the length of the Cochlea.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.104-106
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• 2005

In this paper, 3-dimensional magnetic field of coil is analyzed by using biot-sarvart law considering singularity. The RMSP(reduced magnetic scalar potential) arc employed in order to reduce the number of unknown variables in FEM(Finte Element Analysis) or BEM(Boundary Element Method). It Is necessary to calculate magnetic field of souce current when RMSP is used. Biot-savart law is generally used. it is difficult to calculate the field when the source point is in inside the coil. To integrate using gaussian quadrature, the cross section of coil is divided considering the position of field point when field point is inside coil. The proposed method shows good agreement of magnetic field compared with FEMLAB, OPERA3D.

• 전기의세계
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• v.28 no.11
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• pp.45-51
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• 1979

Finte element methods are developed for the initial distribution problems which contain the surge potential circuits of high voltage transformer windings. The initial distribution of surge voltages in transformer windings are useful to the work to a practical engineering basis. However, the conventional methods of analyzing them so far are much complicated for practical designs. In this paper, the ability to solve surge potential field problems underlies the development of descreting methods to a lodal capacitive distribution-coefficients for determing the surge voltage relationship among a set of transformer coils. A practical example-the modeling of an antioscillation shield coil winding and hisercap winding is used to illustrate and evaluate these methods.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.4
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• pp.1-11
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• 1980

Stiffened plates are commonly used as a component of ship's structures. Most frequently symmetrically stiffened plates are used, but some of stern structures and any specified parts are often constructed with eccentrically stiffened plates. The problems of these eccentrically stiffened plates have been studied rarely, and the results of eccentricity effect of eccentrically stiffened plates are not available. This paper deals with the analysis of eccentrically stiffened plates in the linear elastic range. The derivation of the stiffness matrix was carried out by finite element method for which the isoparametric element was adopted. To show the effect of eccentricity, the deflection at the center under the uniformly distributed and the concentrated load of simply supported and clamped plate models are computed respectively in accordance with the eccentricity of the stiffener. As shown in the results of computations, the eccentricity effect of concentrated load case is greater than that of distributed load case and that of simply supported boundary condition is greater than that of clamped boundary condition. The higher eccentricity of stiffener is, the smaller the effect of stiffener becomes, therefore scantling of eccentrically stiffened plates should be considerably greater than those of symmetrically stiffened plates.