• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.496-499
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• 2009

본 논문은 기하학적 비선형성을 가진 보존적 단일 하중 매개변수의 탄성 상태 공간구조의 분기이론에 관한 수치 해석적 기본 방법 및 경로 추적, pin-pointing, 경로 전환을 기술하고 있다. 비선형 탄성 불안정 상태는 극한점과 분기점으로 분류될 수 있으며, 평형경로상의 평형점의 계산 및 평형경로상의 특이점을 찾기 위한 pin-pointing 반복계산을 수행하는 일반적인 비선형 수치해석법으로 극한점을 계산할 수 있다. 그러나 분기좌굴 해석을 위해서는 좌굴 후 분기경로의 추적을 위한 분기경로 전환 알고리즘이 추가적으로 필요하다. 본문에서는 에너지이론에 기초한 일반 탄성안정이론을 소개하고, 평형경로 추적, 분기 좌굴점을 찾기 위한 직접법과 분기경로 전환에 관한 이론을 전개한다. 분기좌굴 해석예제로 트러스로 이루어진 스타돔, 핀지지의 평면아치, 평면프레임, 3차원 공간프레임의 분기좌굴 해석을 수행하여 본문에서 제시한 수치해석법의 정확성 및 실용성을 검증한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.726-727
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• 2015

본 논문은 IPMSM(Interior Permanent Magnetic - Synchronous Motor) 구동 시에 나타나는 전자기력의 기본파 성분의 진동을 분석하였다. 대상 전동기로는 크기가 같고 동일 출력을 내는 14극 12슬롯, 14극 18슬롯 IPMSM을 선정하였다. 두 전동기의 Vibration Order를 수식적으로 검토한 결과 14극 12슬롯 전동기가 14극 18슬롯 전동기에 비해 전자기력의 기본파 성분이 진동에 취약함을 확인하였고, 이를 유한요소해석(FEA)을 통해 검증하였다. 검토결과를 바탕으로 전자기력의 기본파 성분 진동저감을 위한 극 수 슬롯 수 조합에 대해서 분석하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.495-501
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• 2009

In this paper, a numerical anchor bond-slip model is proposed to improve the numerical simulation of concrete-steel structures connected with steel anchor bolts and subjected to extreme cyclic loading. The suggested bond-slip model is composed of a group of nonlinear uniaxial connector elements and its parameters can be determined by calibrating the model with pull-out test data. Numerical analysis results from simulating a concrete foundation-steel column structure using the proposed bond-slip anchor model, which is implemented based on Abaqus elements, and the perfect-bond anchor model are compared with the experimental results. It is concluded that a reasonable anchor bond-slip model is required to realistically simulate concrete-steel structures subjected to extreme cyclic loading, and the proposed anchor bond-slip model shows acceptable performance in the present numerical analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.4
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• pp.11-24
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• 1990

The effect of end restraints for adjoining members is the different variables influencing the column ultimate strength and the behavior. The propose of this study is to analyze eccentrically loaded reinforced concrete columns with the end restraind effect having rectangular cross-section and general boundary conditions. Accordingly, this investigation are to construct a typical analytical model of the reinforced concrete columns with general end boundary conditions. The mechanical components of the analytical model are to be rationally defined the actual behavior as possible, and the different variables influencing the behavior and the ultimate strength of the reinforced concrete columns are investigated by using a parametric study.

• Computational Structural Engineering
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• v.4 no.1
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• pp.121-132
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• 1991

The purpose of this study is to analyze concentrically loaded reinforced concrete columns with the restrained effect having rectangular cross-section and general boundary conditions. Accordingly, this investigation is to construct a typical analytical model of the reinforced concrete columns with general boundary conditions. The mechanical components of the analytical model are to be rationally defined so as to model the actual behavior as closely as possible, and the ultimate strength of the reinforced concrete columns are investigated by end restrained effect.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.773-778
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• 2002

강우시 불포화 자연사면의 파괴메커니즘을 규명하기 위하여 사면내 모관흡수력의 변화를 고려한 안정해석을 수행하였다. 사면에는 강우계, Tensiometer, Pizometer, Water mock, 경사계 등이 설치되었으며 강우시 사면내 부간극수압과 임시지하수위의 거동을 관찰하였다. 실내실험으로부터 불포화 사면의 안정해석을 위하여 입력 값으로 사용되는 불포화투수계수, 불포화강도정수를 시료의 No.200체 통과량과 건조밀도를 기준으로 경험계수를 이용하여 추정 사용하였다. 강우의 침투로 인한 사면내 부간극수압의 분포는 계측값과 수치해석결과가 차이를 보였으며 이는 불포화 흐름시 흙속의 공기의 영향, 강우의 나무와 수풀에 의한 중간차단효과 및 증발의 영향을 해석에 고려하지 못했기 때문으로 사료된다. 사면안정해석결과 강우초기 모관흡수력을 고려하는 경우 약 10%의 안전율의 증가를 나타냈으며, 침투가 진행되면서 그 차이는 좁아져 임시지하수위가 표층까지 도달했을 때 흡수력을 고려하지 않는 해석과 안전율은 일치하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.303-314
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• 2010

A study for the nonlinear analysis method of prestressed concrete(PSC) girders with external tendons is presented. The PSC girders with external tendons show the complex nonlinear behavior due to the slip of external tendons at deviator and the change of eccentricity between the girders and external tendons. The external tendon between anchorage-deviator or deviator-deviator is modeled as an assemblage of the curved elements. The slip effect of the external tendon at deviator is taken into account using the force equilibrium relationship between the friction force and the driving force at each deviator. The finite element model and analysis method of the external tendon suggested herein are integrated in the nonlinear analysis program of segmentally erected PSC frames developed by the authors. The proposed analysis method is verified through the comparison of the analysis and experimental results obtained from other investigators. From the ultimate analysis results of PSC beams with external tendons having different number of deviators, the yielding and ultimate loads of PSC beams found to be increased as the number of deviators are increased. In addition, the ultimate capacity of the PSC beam increases according to the increase of friction coefficient between deviator and external tendon, whereas found to decease over the certain value of friction due to the effect of the moment transmitted to the member by the friction force exerted from the external tendon.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.966-969
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• 2011

본 논문에서는 자동차용 Battery Post Terminal Clamp의 응력감소를 위한 설계에 있어, ANSYS Workbench 11.0을 이용한 유한요소 구조해석을 하였다. 체결 시 볼트 조임에 따라 가해지는 힘에 따른 응력집중 및 변형을 고려하였고, Battery Post Terminal Clamp에 응력이 집중되어 소성변형이 예상되는 부분에 대한 형상을 변형 하였을 때, 발생 응력이 극한 인장 강도 이하로 감소됨을 확인하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.182-189
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• 2002

This paper is concerned with a collapse behavior analysis for a thin-walled structure considering farming effects. Numerical simulation is carried out with a finite element limit analysis in order to identify forming effects on collapse behavior of a thin-walled structure such as an S-rail. The formed S-rail contains fabrication histories such as residual stress, work hardening, non-uniform thickness distribution and geometric changes resulted from the forming process. The collapse behavior analysis of an S-rail with forming effects leads to different results from that without such effects. The present study deals with the collapse analysis of the S-rail fabricated with the typical forming, trimming and springback processes. Collapse properties such as the collapse load, the collapse mode and the energy absorption are calculated and investigated In order to identify forming effects. It is fully demonstrated that the design of thin-walled structures needs to consider the forming effects for a proper assessment of the load-carrying capacity and the deformation of the formed structures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6521-6526
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• 2013

Elastic and nonlinear ultimate strength analyses were conducted to examine the effects of the stiffness and slenderness of flat-type stiffeners on ultimate in-plane strengths of a stiffened plate system. Although it is not feasible to consider local buckling in the stiffeners in elastic analysis, it was confirmed that the in-plane strengths of the stiffened plate system can be achieved by antisymmetric buckling mode when a certain level of stiffness in the stiffeners is provided. Nonlinear ultimate strength analysis, in which initial imperfection and residual stress are incorporated, showed that the ultimate strengths are sensitively affected by the mode shapes for initial imperfections. The slenderness limit for flat-type stiffeners in KHBDC (Korean Highway Bridge Design Code) was evaluated as conservative compared to the analysis results.