• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.185-190
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• 1994

본 연구에서는 와선 지배방정식의 계산을 위해 쌍곡선 blending 함수를 이용하여 와선운동의 정확한 계산을 할 수 있었고 이 방법을 통하여 임의로 거동하는 와선이 강체구와 간섭하는 경우의 3차원 유동장에 대한 해석과 이에 의한 쌍극 음향장 해석을 수행하였다. 경계치 적분방법을 통해 강체구에 작용하는 힘을 계산할 수 있었고 이 방법은 물체의 형태에 구애 받지 않으므로 임의 형상에 대해서도 유동장과 음향장 계산이 가능하다고 본다.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.4
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• pp.93-104
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• 2000

적충되어 있는 다중 블록 시스템은 역사적 건물이나 문화재등에 자주 사용되고 있다. 이러한 구조시스템은 지진에 매우 취약하고, 특히 세장한 구조물인 경우에는 낮은 수준의 지반가속도에 대해서도 전도가 일어날 수 있다. 지진으로부터 이러한 구조물을 보호할 수 있는 방법중의 하나로써 지진격기받침의 사용을 들 수 있으나, 아직 격리받침이 설치되어 있는 다중블록의 거동에 대해서는 잘 알려지지 않는 실정이다. 이 논문에서는 각각 P-F 시스템, FPS, LRB 시스템이 설치되어 있을때의 세장한 강체 블록의 동적거동에 대해 살펴보았다. P-F 시스템과 FPS에서의 마찰모델은 Coulomb의 마찰법칙을 이용하였도, 상부구조물은 붙음(stick)모드와 록킹(rocking) 모드만이 존재하도록 가정하였다. 충격은 개별요소법(distinct element method, DEM)을 이용해 기술하였고, 조화입력운동에 대한 응답을 조사하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.19-28
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• 2013

In a shear wall-frame structural system, the structural response is determined by the interaction between the shear wall in bending mode and the frame in shear mode. In order to effectively consider these characteristics of a shear wall-frame structure, the simplified numerical model using the T-shape rigid body was suggested in the previous study. Based on the previously proposed model, an efficient numerical model for a wall-frame structure with an eccentric core has been proposed in this study. To this end, the previously proposed 2D model is extended to the 3D model and it is enhanced by considering torsion effects. As a result, the enhanced model can be applied to the analysis of a wall-frame structure with an eccentric core as well as a centric core.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.6
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• pp.67-86
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• 2009

In this study, a 3D transmitting boundary in water-saturated transversely isotropic soil strata has been developed based on u-w formulation for application to general 3D analysis. Behavior in the far field region is expanded in the Fourier series, and dynamic stiffness for each term is obtained based on the u-w formulation. Transformation of the dynamic stiffness is presented to combine the transmitting boundary with the 3D finite elements for the near field region formulated in a 3D Cartesian coordinate system. The developed transmitting boundary is verified through a comparison of the dynamic behavior of a rigid circular foundation with the results from the existing numerical method. In addition, the developed transmitting boundary is applied to the analysis of the dynamic behavior of rigid foundations of diverse shapes, and the effects of the level of the groundwater table on the dynamic stiffness of a rigid rectangular foundation in the water-saturated transversely isotropic layered stratum are studied.

• Journal of the Korean Geotechnical Society
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• v.23 no.4
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• pp.79-90
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• 2007

Behaviors of instrumented steel sheet piles which are installed in sand ground by vibratory hammer were investigated. Especially, stresses acting on the pile during vibratory driving, efficiency factor which reflects differences between theoretical driving force and actually delivered acting force, justifiability of rigidity of steel sheet pile, dynamic resistance characteristics of soil and penetration characteristics of sheet pile were analysed. According to the field test results it is justifiable that steel sheet pile behaves as a rigid body during vibratory driving. And it can be seen that maximum stress acting on sheet pile section is far less than tensile strength of the material. Value of the maximum section force at sheet pile head was 72% of that estimated from theoretical equation. Magnitudes of displacement amplitudes computed from displacement-time history curve corresponding to four penetration depths were in the range of 16 $\sim$ 75% of that specified by manufacturer.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.145-146
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• 2010

A moment redistribution method was developed for earthquake design of reinforced concrete moment-resisting frames. For a frame designed with strong column-weak beam, the moment redistribution mechanism was investigated. Based on the result, the relationship between redistributed moment and plastic rotation in plastic hinges was established. By using the relationship, we developed a method for the evaluation of plastic rotations during the moment redistribution, addressing the effects of various design parameters including member stiffness, load condition, and plastic mechanism of structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.1
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• pp.1-12
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• 2005

An analytical procedure to analyze reinforced concrete (RC) beams subject to monotonic loadings is proposed on the basis of the moment-curvature relations of RC sections. Unlike previous analytical models which result the overestimation of stiffnesses and underestimation of structural deformations induced from ignoring the shear deformation and assuming perfect-bond condition between steel and concrete, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end. The advantages of the proposed relation, compared with the previous numerical models, are on the promotion in effectiveness of analysis and reflection of influencing factors which must be considered in nonlinear analysis of RC beam by taking into account the nonlinear effects into the simplifying moment-curvature relation. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed model to the nonlinear analysis of RC structures.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.89-92
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• 2008

This study investigates the shear behavior of architectural masonry veneer wall reinforced with specific reinforcement details proposed by this study. For this purpose, experimental tests were conducted using one un-reinforced masonry(URM) wall specimen and three reinforced masonry(RM) wall specimens under quasi static cyclic loads. Un-reinforced(plain) masonry wall is expressed that behavior and failure mode are different for aspect ratio(L/H) and axial compressive force. The test variables are wall aspect ratio and presence of reinforcement. These specimens are masonry structure for architectural clading that is not to exist the axial compressive force. thus the axial compressive force is excepted from test variable. Test result, Behavior of specimens are dominated over rocking mode, but final failure modes are combined with different behaviors. And FEMA273 has proposed the equation of shear strength of masonry pier subjected to in-plane loading. Shear strength equations are classified four types of failure mode that is Rocking, and Toe-Crushing, Bed-Joint-Sliding and Diagonal-Tension. FEMA273 equations predict the behavior modes well, but shear strength is shown in different result.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.237-245
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• 2008

We developed a computational method on coupled dynamics of tracked vehicle on seafloor and long flexible pipe. The tracked vehicle is modeled as rigid-body vehicle, and the linked flexible pipe is discretized according to a lumped-parameter model. The equations of motion of the rigid-body vehicle on the soft seafloor are combined with the governing equations of flexible pipe dynamics. Four Euler parameters method is used to express the orientations of the vehicle and the flexible pipe. In order to solve the nonlinear coupled dynamics of vehicle and flexible pipe an incremental-iterative formulation is implemented. For the time-domain integration $Newmark-\beta$ method is adopted. The total Jacobean matrix has been derived based on the incremental-iterative formulation. The interactions between the dynamics of flexible pipe and the mobility of the tracked vehicle on soft seafloor are investigated through numerical simulations in time domain.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.199-202
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• 1998