• Water for future
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• v.25 no.3
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• pp.97-104
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• 1992

The distributed hydrologic models are widely applied to estimate the storm-runoff with spatial variability in watershed characteristics and rainfall pattern. This study was aimed to introduce the event-oriented storm runoff model using finite element method, and to try it's applicability on small watershed. Yeonwha watershed was selected and 14 storm events in 1991 were used for the finite element model, and the simulation results were compared with hydrologic quantities.

• Journal of Korean Port Research
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• v.14 no.1
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• pp.97-105
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• 2000

This paper presents an automatic mesh generation considering water depth, which is based on the depth interpolation. The key feature of this method is that the position of a mesh on any depth in the shallow water area can be generated. The Examples are carried out, and the results are shown to be good. This method is shown to be a useful and powerful tool for the flow calculation for the seabed topography.

• Geotechnical Engineering
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• v.6 no.1
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• pp.25-34
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• 1990

The finite element and boundary element methods of underground analysis are both well established numerical techniques for determination of stress and displacement distributions at underground excavation. The finite element method presents antithetical advantages and limitations. Complex constitutive behaviour may be modelled, at the expense of numerical efficiency and, for infinite domain, inadequate representation of remote bounadry conditions. The inherent advantages of the boundary element method are the ease with which infinite domain problems may be analysed, and the efficiency of analysis typically associated with a boundary value solution procedure. Application of the method is limited by the requirements linear constitutive behaviour for the medium. A combined of the finite element and boundary element methods of underground analysis is shown to preserve the advantages of each procedure, and, eliminates their individual disadvantages. Procedures employed in this papers described combined FEBEM algorithm. Solutions of underground excavation verifying the performance of combined FEBEM code are compared with theoretical solution, boundary element solution and finite element solution.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1202-1208
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• 2009

An inverse finite element (FE) model parameter estimation algorithm can be used to characterize mechanical properties of biological tissues. Using this algorithm, we can consider the influence of material nonlinearity, contact mechanics, complex boundary conditions, and geometrical constraints in the modeling. In this study, biomechanical experiments on macro and micro samples are conducted and characterized with the developed algorithm. Macro scale experiments were performed to measure the force response of porcine livers against mechanical loadings using one-dimensional indentation device. The force response of the human liver cancer cells was also measured by the atomic force microscope (AFM). The mechanical behavior of porcine livers (macro) and human liver cancer cells (micro) were characterized with the algorithm via hyperelastic and linear viscoelastic models. The developed models are suitable for computing accurate reaction force on tools and deformation of biomechanical tissues.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.82-90
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• 1993

전자파에 의한 산란현상의 해석은 지금까지 주로 시간조화함수의 형태를 지닌 전원에 의한 정 상상태의 산란에 관하여 이루어졌다. 그러나 레이다나 피파괴 검사, 전송선로 점검 등의 응용에서는 주로 펄스형태의 전자파를 사용하며, 따라서 시간에 따라 변화하는 함수형태의 전원에 의한 전자파의 산란해 석이 중요한 문제로 등장하였다. 또한 통신선로에서 외부의 잡음에 대한 혼신 등을 해석하거나, 낙뢰가 송 전선로에 미치는 영향을 해석하는 데에도 펄스신호의 산란해석이 필수적이다. 일반적인 함수의 형태를 지닌 전원에 의한 산란현상을 해석하기 위해서는 전원함수를 Fourier 변환하 여 주파수 영역의 스펙트럼을 구하고, 주파수영역에서의 산란해를 이용하여 Fourier 역변환을 하여 시간 영역의 해를 구할 수 있다. 주파수 영역에서의 산란판의 해를 Fourier 역변환 하기 위해서는 적분을 행하여야 하며, 일반적으로 적분과정에서 매우 복잡한 계산이 필요하고, 산란체의 구조가 복잡하여 해석 적인 해를 구할수 없는 경우에는 해석적으로 시간영역의 해를 구하는 것이 불가능하다. 시변 함수에 의 한 산란파를 구하기 위한 수치해석적 방법으로는 모멘트방법이나 유한요소법(Finite Element Method), 경계요소법(Boundary Element Method), 유한차분법(Finite Difference Method)등이 있으며, 해석적 해 를구할 수 없는 경우에 적용할 수 있는 반면에 많은 계산량이 요구된다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.37-49
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• 2000

This paper is for the first essential study on the development of unified finite element formulations for solving problems related to the dynamics/thermoelastics behavior of solids. In the first part of formulations, the finite element method is based on the introduction of a new quantity defined as heat displacement, which allows the heat conduction equations to be written in a form equivalent to the equation of motion, and the equations of coupled thermoelasticity to be written in a unified form. The equations obtained are used to express a variational formulation which, together with the concept of generalized coordinates, yields a set of differential equations with the time as an independent variable. Using the Laplace transform, the resulting finite element equations are described in the transform domain. In the second, the Laplace transform is applied to both the equation of heat conduction derived in the first part and the equations of motions and their corresponding boundary conditions, which is referred to the transformed equation. Selections of interpolation functions dependent on only the space variable and an application of the weighted residual method to the coupled equation result in the necessary finite element matrices in the transformed domain. Finally, to prove the validity of two approaches, a comparison with one finite element equation and the other is made term by term.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1183-1192
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• 1989

본 논문에서는 평면변형률 상태하에서 안정하게 성장하는 균열선단에 집중 되어있는 강소성역의 해석에 역점을 두어 재결정법과 탄.소성유한요소법을 도입하여 안정 성장균열 선단에 형성되는 균열 성장저항에 직접적인 영향을 미치고 있는 소성 역의 크기나 형태에 대한 실험 및 해석을 하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.3
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• pp.345-352
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• 1985

본 연구에서는 내류(internal flow)에서 유로가 비대칭으로 급확대될 경우의 박리현상과 유동현상을 고찰하였다. 비대칭 급확대 채널에서의 층류영역에서 난류영 역까지의 유동현상을 B.F. Armaly, C.E. Thomas는 실험적 해석과 유한요소법을 사용하 여 이론적 해석을 하였고 Donald. M. Kuehn, Denham & Patrick, Kwon, Patrick J. Ro- ache, Anand Kumar등은 같은 모델에 대해서 실험적 해석과 유한차분법을 사용하여 이 론적 해석을 하였으며 지금까지의 유한해석법에 의한 연구는 입구와 출구조건이 같은 경우 및 밀폐 공간 혹은 한면의 속도가 주어지는 밀폐공간등에 대해 수행되어 왔으나 본 연구에서는 입구와 출구조건이 같지 않은 2차원, 비대칭 급확대 채널에서의 유동현 상을 유한해석법으로 해석하여 실험치와 비교하였다.

• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.61-68
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• 2007

The problem on cyclic plate load tests was analyzed by finite element method using an anisotropic hardening constitutive model. The constitutive model was coded to user subroutine in ABAQUS. Using the result of the analysis, Young's moduli corresponding to various strain levels were evaluated by a back calculation method and were very similar to those of input. On the basis of the back calculation method plate loading tests were verified. As a result, deformation moduli could be evaluated practically from cyclic plate load tests with respect site conditions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.414-417
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• 2005

Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.