• Computational Structural Engineering
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• v.1 no.2
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• pp.26-33
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• 1988

유한요소해석프로그램들의 적용대상이 최근들어 다(多) 자유도의 비선형문제로 확대됨에 따라 컴퓨터의 계산속도가 특히 중요한 제한조건으로 대두되기 시작하였으며 금속성형해석, 자동차 등의 충돌해석(자유도가 2만-6만), 토질 및 콘크리트 등의 점소성해석과 더불어 항공기, 터빈 등의 열응력해석 및 동적해석 등에 있어서는 막대한 계산시간으로 인하여 해석의 효율성에 대한 문제가 제기되고 있다. 따라서 슈퍼컴퓨터를 포함하여 고속연산기능을 가진 병렬처리컴퓨터를 이용하여 유한요소해석을 수행하여야 할 필요성이 증가하고 있다. 88년 9월중에 한국과학기술원 시스템공학센터에 현존하는 슈퍼컴퓨터중 최상위 성능을 가진 CRAY2S가 설치됨에 따라 국내에도 슈퍼컴퓨터시대가 열리게 되었으며 따라서 본 고에서는 CRAY2S의 시스템개요 및 응용소프트웨어에 대하여 소개하고 슈퍼컴퓨터를 이용한 유한요소해석에 관하여 간략히 기술하고저 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.201-202
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• 2009

The objective of this paper is to develop nonlinear analysis method using fiber element. The program is based on flexibility method and developed for analyzing bernoulli's beam element. Using fiber element, three dimensional effects, such as concrete confinement can be incorporated into the uniaxial stress-strain relationship. In addition, most appropriate modeling method is used for application of bond-slip and shear effects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.865-873
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• 2013

In this paper, numerical methods for wrinkle prediction of thin membrane were studied by finite element analysis. Techniques using membrane and shell elements were applied for triangular membrane. In case of membrane element method, the wrinkling was accounted for by the wrinkle algorithm of property modification, which was implemented to ABAQUS as a user subroutine. In case of shell method, geometrically nonlinear post-buckling analysis was performed to obtain the wrinkle deformation explicitly. The wrinkling deformation was induced by seeding the mesh with a random geometric imperfection. The results were investigated focusing on the mesh convergence and the solution accuracy.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.1
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• pp.145-156
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• 1993

An improved analysis model for material nonlinearity induced by elasto-plastic deformation and damage including large strain response was proposed. The elasto-plastic-damage constitutive model based on the continuum damage mechanics approach was adopted to overcome limitations of the conventional plastic theory, which can manage the anisotropic tonsorial damages evolved during time-independent plastic deformation process of materials. Updated Lagrangian finite element formulation for elasto-plastic damage coupling problem including large deformation, large rotation and large strain problems was completed to develop a numerical model which can predict all kinds of structural nonlinearities and damage rationally. Finally, a finite element analysis code for the 2-dimensional plane problem was developed and the applicability and validity of the numerical model was investigated through some numerial examples. Calculations showed reasonable results in both geometrical nonlinear problem due to large deformation and material nonlinearity including the damage effect.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.335-341
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• 1996

유한차분 감소를 이용한 감도해석 및 구조변경 프로그램을 개발하고 수치해석을 수행하여 다음과 같은 결론을 얻었다. 1) 유한요소 모델로부터 얻은 유한차분감도를 이용한 결과가 미분을 이용한 감도해석법의 결과에 비해 큰 차이없이 타당한 결과를 제시하여 주는 것을 확인하였다. 2) 복잡한 판구조물의 형상을 등가의 동특성을 갖는 보를 이용하여 모델링하고, 보의 단면치수를 설계변수로하여, 구조변경을 수행함으로써 효율적인 해석을 수행하였다. 3) 혀상이 복잡한 판 구조물의 형상 및 치수등 비선형적인 요소의 변경으로 인한 구조변경시 유한차분 감도 해석법을 이용한 구조변경이 좋은 결과를 나타내는 것을 확인하였고, 이로써 유한차분을 이용한 감도해석법이 형상최적화(shape optimization)에 적합한 방법임을 알 수 있었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.485-490
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• 2015

This paper presents development of a geometrically nonlinear triangular planar element including rotational degrees of freedom, based on the co-rotational(CR) formulation. The CR formulation is one of the efficient geometrically nonlinear formulations and it is based on the assumptions on small strain and large rotation. In this paper, modified CR formulation is suggested for the developemnt of a triangular planar element. The present development is validated regarding the static and time transient problems. The present results are compared with the results predicted by the previous researchers and those obtained by the existing commercial software.

• Journal of Korean Association for Spatial Structures
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• v.16 no.3
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• pp.31-36
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• 2016

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.399-409
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• 2012

The flexural behavior of HSB plate girder with a non-slender web, due to inelastic lateral-torsional buckling, under uniform bending was investigated by the nonlinear finite element analysis. Both homogeneous sections fabricated from SM570-TMC, HSB600 or HSB800 steel and hybrid sections with HSB800 flanges and SM570-TMC web were considered. The flanges and web of selected noncomposite I-girders were modeled as thin shell elements and the geometrical and material nonlinear finite element analysis was performed by the ABAQUS program. The steel was assumed as an elasto-plastic strain hardening material. Initial imperfections and residual stresses were taken into account and their effects on the inelastic lateral-torsional buckling behavior were analyzed. The flexural strengths of selected sections obtained by the finite element analysis were compared with the nominal flexural strengths from KHBDC LSD, AASHTO LRFD, and Eurocode and the applicability of these codes in predicting the inelastic lateral torsional buckling strength of HSB plate girders with a non-slender web was assessed.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.3
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• pp.31-40
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• 2002

The purpose of this study is to investigate the seismic behavior of RC bridge piers and to provide the data for developing improved seismic design criteria. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST(reinforced concrete analysis in higher evaluation system technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. n boundary plane at which each member with different thickness is connected, local discontinuity in deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel and concrete. In the companion paper, the proposed numerical method for seismic damage evaluation of RC bridge piers is verified by comparison with the reliable experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.2
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• pp.83-91
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• 2001

본 연구에서는 2차원 평면상에서 자유장응답 해석을 위하여 유한요소-경계요소 조합에 의한 수치해석기법을 개발하였다. 전체 계를 외부영역과 내부영역으로 구분하였다. 외부영역은 동적 다층반무한 기본해를 이용한 경계요소로 모형화되고 내부영역은 유한요소로 모형화하여 조합하였다. 다층지반의 외부에서 입사하는 지진에 의한 지진응답해석을 수행하기 위하여 동적기본해를 이용한 자유장응답해석을 수행하였다. 지진응답해석에서는 지반의 전단병형률에 따라 변화하는 비선형특성을 모형화하기 위해 등가선형화기법을 적용하였다. 지진응답해석의 검증에 의하여 해석결과를 상용프로그램의 결과와 비교하였다. 결과적으로 지진응답해석을 효과적으로 수행할 수 있는 수치해석기법을 개발하였고 구조물이 있는 경우로의 확장돠 가능하게 되었다.