• Structural Engineering and Mechanics
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• 제5권1호
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• pp.1-19
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• 1997

A numerical procedure for dynamic analysis of structures including lateral-torsional coupling, axial force effect and soil-structure interaction is presented in this study. A simple soil-structure system model has been designed for microcomputer applications capable of reflecting both kinematic and inertial soil-foundation interaction as well as the effect of this interaction on the superstructure response. A parametric study focusing on inertial soil-structure interaction is carried out through a simplified nine-degree of freedom building model with different foundation conditions. The inertial soil-structure interaction and axial force effects on a 20-storey building excited by an Australian earthquake is analysed through its top floor displacement time history and envelope values of structural maximum displacement and shear force.

• 한국지반공학회논문집
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• 제21권2호
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• pp.37-46
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• 2005

최근 지진공학 제반분야의 연구동향은 지진발생시 구조물의 거동을 보다 합리적/경제적으로 고려하는 내진성능 목표 개념에 입각하여 많은 향상을 성취하고 있다. 특히, 실제 지진에서 관측된 자료를 사용하여 시방기준과 해석기법에 많은 보완이 이루어지고 있는 실정이다. 그러나, 지반-구조물 상호작용에 대한 연구는 경험적으로 입증된 해석방법의 정립이 아직까지 과제로 남아있는 분야이다. 이러한 취지에서, 본 연구에서는 구조물과 지표면 자유장 운동의 강진기록이 잘 관측되어 있는 2매 사이트를 선택하여, 입/출력 자료를 가지고 시스템 특성치즐 추정할 수 있는 System Identification 기법을 이용하여 지반-구조물 상호작용의 해석기법 중 가장 보편적이며 비교적 간단한 주파수 영역의 Impedance 함수를 계산하고 그 결과를 바탕으로 관성력에 의한 지반-구조물 상호작용에 대한 고찰을 수행한다.

• 한국대기환경학회지
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• 제16권2호
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• pp.165-178
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• 2000

In this study the effects of block distance have been investigated on the particle deposition efficiency in the collecting cell of two-stage electrostatic precipitator by numerical analysis. Particle trajectories have been changed by the electrostatic and inertial force of particle with the inlet velocity electrostatic number and particle diameter. The total deposition efficiency has a minimum value by the interaction between the effect of particle inertial force and electrostatic force in the collecting cell. The increase of block distance makes the total deposition efficiency decrease under the range of the particle size which has the minimum deposition efficiency. However beyond the range of particle size which has minimum deposition efficiency total deposition efficiency has no trend with the variation of block distance.

• 한국지진공학회논문집
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• 제1권1호
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• pp.11-17
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• 1997

그 동안 구조물에 대한 지진해석이 기초와 지반의 특성을 무시하고 기초가 매우 단단한 것으로 가정하고 수행되었다. 최근 구조물-지반 상호작용에 관한 연구결과 구조물 지진거동이 기초와 지반의 특성에 따라 심하게 영향을 받을 수 있다는 것이 알려졌다. 전형적인 구조물-지반 상호작용 영향은 무한강성 무질량 기초의 운동학적 상호작용과 지반과 구조물 사이에서 발생하는 관성상호작용이다. 운동학적 상호작용은 묻힌 기초의 경우에는 중요하지만, 수직으로 전달되는 지진파를 받는 지표면상 기초의 경우에는 무시될 수 있다. 이 논문에서는 멕시코시티 4개 건물에 대해 관성상호작용만을 고려하고 1985년 멕시코시티 동서방향 지진기록을 사용하여 구조물의 지진거동을 조사하였다. 연구는 지표면상 기초나 말뚝기초를 가진 구조물에 대해 선형 및 비선형 지반조건을 고려하여 수행하였으며, 연구결과를 매우 견고한 기초를 갖는 구조물에 대한 것과 비교하였다.

• 한국대기환경학회지
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• 제16권6호
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• pp.641-652
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• 2000

The effect of block arrangement has been investigated on the particle deposition in the specified collecting cell of two-stage electrostatic precipitator by numerical analysis. Recirculation zone existed at the downstream of the block in the collecting cell, and the particles entering the recirculation zone were deposited on the collecting plate. Particle trajectory and deposition had considerably different phenomenon according to electrostatic and inertial effect, which depended on inlet mean velocity, electrostatic number, and particle diameter in the collecting cell. The total collection efficiency reached a minimum value through an interaction of electrostatic and inertial effect. In the computational domain, total collection efficiency for the case of two blocks in the computational domain was more than that of one block at the relative small electrostatic number. However as the block distance and inertial effect increased, the difference between the collection efficiency of two cases decreased. In the range of relatively small particle size total collection efficiency was always superior to particle collection efficiency that was predicted by Deutsch equation.

• 한국지진공학회논문집
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• 제28권4호
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• pp.165-170
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• 2024

This study investigated the impact of soil-structure interaction on multi-degree-of-freedom structures using the shallow-foundation Winkler model, known as the BNWF model. The model's period was determined through eigenvalue analysis and compared to results obtained from FEMA's formula. Results indicated that considering the soil, the structure's period increased by up to 8.7% compared to the fixed-base model, aligning with FEMA's calculations. Furthermore, with adequate ground acceleration, roof displacement increased by 3.4% to 3.8%, while base shear decreased by 4% to 10%. However, roof displacement and base shear increased in some earthquake scenarios due to spectral shape effects in regions with extended structural periods. Foundation damping effects, determined through the foundation's moment-rotation history, grew with higher ground acceleration. This suggests that accounting for period elongation and foundation damping can enhance the seismic design of multi-degree-of-freedom structures.

• 전산구조공학
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• 제6권2호
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• pp.87-93
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• 1993

최근 구조물의 동적해석에서 구조물-지반 상호작용이 구조물의 동적거동에 미치는 영향이 매우 중요하다는 것이 인식되어지고 있다. 이 논문에서는 관성력에 의한 구조물-지반 상호작용이 건물의 동적거동에 미치는 영향을 살펴보기 위하여 유한요소기법을 이용하여 이론적인 연구와 시험적 조사 (Experimental Investigation)연구를 수행하였다. 이론적 연구는 균질한 지반위에 기초가 약간 묻혀있는 낮고 강성이 강한 건물과 높고 가느다란 건물 두개에 대하여 수행하였으며, 시험적 조사연구는 1985년 멕시코 대지진을 겪은 말뚝기초위에 세워진 두개의 건물에 대해 수행하였다. 이 연구 결과를 살펴보면 구조물-지반 상호작용이 구조물에 미치는 주된 영향은 고유주파수 감소와 유효감쇄비 증가인데, 그 영향이 구조물 동적거동에 심각한 영향을 미치는 경우가 있기 때문에 구조물-지반 상호작용 영향을 구조물 동적해석시 필히 고려해야 한다는 것이다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.292-300
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• 2024

Kinetic simulations have been performed on an Inertial Electrostatic Confinement Fusion (IECF) device. These simulations were performed using the particle-in-cell (PIC) method to analyze the behavior of ions in an IEC device and the effects of some parameters on the Confinement Time (CT). CT is an essential factor that significantly contributes to the IEC's performance as a nuclear fusion device. Using the PIC method, the geometry of a two-grided device with variable grid radius, the number of cathode grid rings, variable pressure and different dielectric thickness for the feed stalk was simulated. In this research, with the development of previous works, the interaction of particles was simulated and compared with previous results. The simulation results are in good agreement with the previous results. In these simulations, it was found that with the increase of the dielectric thickness of the feed stalk, the electric field was weakened and as a result, the confinement time was reduced. On the other hand, with the increase of the cathode radius, the confinement time increased. Using the results, an IEC device can be designed with higher efficiency and more optimal CT for ions.

• 한국지반공학회지:지반
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• 제6권3호
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• pp.13-30
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• 1990

본 연구에서는 깊은 기초의 내진설계에 적용하기 위해, 지진하중에 의한 말뚝기초의 응답을 산출하여 비교, 검토하였다. 본 연구에서 사용된 해석 방법은 Subgrade Reaction Theory 및 탄성해석법과 같은 유사정적 해석방법, Prakash및 Gazetas가 각각 제안한 동적 해석방법이며, 예제해석을 통해 말뚝의 최대 상대변위 및 최대 휨모멘트를 위의 각 방법을 이용해서 산출하였고, 그 결과를 각각 비교하였다. 또한 말뚝의 군효과를 근사적으로 고려하여 Novak에 의해 수행된 실험 결과와 비교하였다. 해석결과를 분석해 볼 때 Kaynia와 Kausel이 제안한 동적 Group Interaction Factor Approach 에 의한 땅법 및 Gazetas가 제안한 방법의 최대 상대변위는 실측치와 부합하게 산정되었으며, Prakash 가 제안한 방법과 정적 Group Interaction Factor Approach에 의한 변위 및 휨모멘트는 과대평가되었다. 그러므로, 말뚝의 내진설계시에 동적 Group Interaction Factor Approach와 결합한 유사정적해석 을 사용하고 Gazetas가 제안한 동적방법에 의해 이를 검토하는 것이 바람직하다.

• Wind and Structures
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• 제38권4호
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• pp.261-275
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• 2024

Before performing an experimental study on the downburst-generated wave, it is necessary to examine the scale effects and corresponding corrections or compensations. Analysis of similarity is conducted to conclude the non-dimensional force ratios that account for the dynamic similarity in the interaction of downburst with wave between the prototype and the scale model, along with the corresponding scale factors. The fractional volume of fluid (VOF) method in association with the impinging jet model is employed to explore the characteristics of the downburst-generated wave numerically, and the validity of the proposed scaling method is verified. The study shows that the location of the maximum radial wind velocity in a downburst-wave field is a little higher than that identified in a downburst over the land, which might be attributed to the presence of the wave which changes the roughness of the underlying surface of the downburst. The impinging airflow would generate a concavity in the free surface of the water around the stagnation point of the downburst, with a diameter of about two times the jet diameter (D_jet). The maximum wave height appears at the location of 1.5D_jet from the stagnation point. Reynolds number has an insignificant influence on the scale effects, in accordance with the numerical investigation of the 30 scale models with the Reynolds number varying from 3.85 × 10⁴ to 7.30 × 10⁹. The ratio of the inertial force of air to the gravitational force of water, which is denoted by G, is found to be the most significant factor that would affect the interaction of downburst with wave. For the correction or compensation of the scale effects, fitting curves for the measures of the downburst-wave field (e.g., wind profile, significant wave height), along with the corresponding equations, are presented as a function of the parameter G.