• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.2
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• pp.153-168
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• 2016

Sloshing phenomenon is a complicated free surface flow problem that increases the dynamic pressure on the sidewalls and the bottom of the storage tanks. When the storage tanks are partially filled, it is essential to be able to evaluate the fluid dynamic loads on the tank's perimeter. In this paper, a numerical code was developed to determine the pressure distribution on the rectangular and trapezoidal storage tanks' perimeters due to liquid sloshing phenomenon. Assuming the fluid to be inviscid, the Laplace equation and the nonlinear free surface boundary conditions were solved using coupled boundary element - finite element method. The code performance for sloshing modeling was validated using Nakayama and Washizu's results. Finally, this code was used for partially filled rectangular and trapezoidal storage tanks and free surface displacement, pressure distribution and horizontal and vertical forces exerted on the tanks' perimeters due to liquid sloshing phenomenon were estimated and discussed.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.208-213
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• 1993

The structural and functional roles of IGS element of T4 td intron in thymidylate synthase activity in vivo were investigated Site-directed mutagenesis was employed to crete mutations of IGS element of T4 td intron, When a U-G pari was changed to a U-C pari in the 5' splice site of P1 stem of td intron, the activity of thymidylate synthase was completely abolished whereas the wild type retained the normal activity of enzyme. When U at 12 position within IGS element was changed to C, the activity of thymidylate synthase was approximately 32% of that of the wild type. Comparison of enzyme activities suggests that IGS element within P1 structure is an essential requirement for splicing of td gene in vivo.

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.64-76
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• 2003

In this work, a new penalty formulation is proposed for the analysis of Mindlin-Reissner plates by using the element-free Galerkin method. A penalized weak form for the Mindlin-Reissner Plates is constructed through the exterior penalty method to enforce the essential boundary conditions of rotations as well as transverse displacements. In the numerical examples, some typical problems of Mindlin-Reissner plates are analyzed, and parametric studies on the order of integration and the size of influence domain are also carried out. The effect of the types of background cells on the accuracy of numerical solutions is observed and a proper type of background cell for obtaining optimal accuracy is suggested. Further, optimal order of integration and basis order of Moving Least Squares approximation are suggested to efficiently handle the irregularly distributed nodes through the triangular type of background cells. From the numerical tests, it is identified that unlike the finite element method, the proposed element-free Galerkin method with penalty technique gives highly accurate solution without shear locking in dealing with Mindlin-Reissner plates.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.1
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• pp.13-20
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• 1999

Not only is it important that the physical properties of the paperboards be appropriate for the intended end use, but the proper arrangement of the component in the built-up board is essential for attaining the optimum moment of inertia and the maximum load-carrying ability in a box. It is known to be impossible to estimate the stress distribution and deflection pattern by experiments or theoretical analysis when the corrugated fiberboard get the bending force. This study was tried theoretical and finite element analysis to analyze structural strength characteristics of corrugated fiberboards. If the linerboard and corrugating medium of every corrugated fiberboards is made from the same material, the location of neutral axis comes close to inside liner in order of DMA, DM, DMB, SW and DW, and moment of inertia of area decreases in order of DMA, DMB, DW, DM and SW. With the finite element analysis, deflection of applied loads represented SW, DM, DMA, and TW in the order of their value.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2370-2378
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• 2009

The enhanced phase angle estimation algorithm is essential to supply the power stably under synchronizing with grid source. In this paper, we are proposed the novel phase angle estimation algorithm and verified the validity of proposed method as simulation with PSIM and experiments. We sort the harmonics element using high-pass filter(HPF) that have the cut-off frequency below basic element and make reverse d-q transformation. So, it can be restored the harmonics element at stationary axis, and we can get the fundamental voltage element of AC grid. Proposed PLL method have a rapid responsibility and a large margin at controller design than conventional method because it have a small phase delay and a sufficient controller gain margin. And, it can reduce the error of voltage rms value and axis transformation according to robust PLL algorithm against the harmonic and phase unbalance.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.168-173
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• 1992

In the design and construction of underground structures, it is essential to accurately predict the structural behavior of the fluid-saturated ground during and after excavation. Terzaghi and Biot established the theory for the behavior of such two phase material. For the purpose of analysing the saturated porous solid system, finite element procedure provides a powerful tool. In this paper, a finite element analysis procedure based upon Biot's theory is presented to evaluate the deformation of solid skeleton and pore pressure of entraped fluid. Teraghi's onf-dimensional and Gibson's two-dimensional problems are solved using Q4 and Q8 element to verify the program validity.

• Journal of Industrial Technology
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• v.18
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• pp.131-138
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• 1998

Numerical modeling for electromagnetic exploration methods are essential to understand behaviours of electromagnetic fields in complex subsurfaces. In this study, a finite element method was adopted as a numerical scheme for the 2.5-dimensional forward problem. And a finite element equation considering linear conductivity variation was proposed when 2.5-dimensional differential equation to couple eletric and magnetic field was implemented. Model parameters were investigated for near-field with large source effects and far-field with responses dominantly by homogeneous half-space. Numerical responses by this study were compared with analytic solutions in homogeneous half-space and compared with other three dimensional numerical results.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.67-76
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• 2022

Power and signal transmission using electromagnetic waves are essential in modern times, and a guided structure is needed to transmit electromagnetic waves efficiently through the desired path. This paper performed an electromagnetic simulation using the in-house code for the 2-D/3-D waveguide using the finite element method. The accuracy of the analysis was verified by comparing it with the results of HFSS, a representative electromagnetic wave simulation software. In addition, the performance of the Absorbing Boundary Condition (ABC), which is essential to truncate the infinite computational domain for computational electromagnetics, was analyzed. Finally, the parallelization technique was applied to accelerate the simulation speed, demonstrating performance improvement.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.9-13
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• 2009

A simple outline for teaching adaptive scheme based finite element method for planar problems as a part of computer aided teaching of structural engineering curriculum is presented. Displacement based finite element formulation for planar problems and representative strain value based adaptive scheme for mesh generation are considered. As examples, a cantilever beam with a concentrated load treated as a planar problem and stretching of a plate with a circular hole are analyzed with displacement based finite element method with adaptive meshes. The examples and outlines show how adaptive based finite element method may become an essential part of computer aided teaching of structural engineering.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.227-232
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• 2006

This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition