• 한국안전학회지
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• 제15권3호
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• pp.96-101
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• 2000

The effects of internal fluid motion have to be considered in the analysis of liquid storage containers. Therefore this thesis developed a three-dimensional boundary element-finite element method for the analysis of rectangular liquid storage containers. The irrotational motion of inviscid and incompressible ideal fluid is modeled by using boundary elements and the motion of structure by finite elements. Coupling is performed by using compatibility and equilibrium conditions along the interface. Dynamic response characteristics of rectangular liquid storage containers such as sloshing motion, hydrodynamic pressure, displacement by fluid-structure interaction are investigated.

• Computers and Concrete
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• 제18권2호
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• pp.179-199
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• 2016

The aim of this study is to investigate arrival direction effects of travelling waves on non-linear seismic response of arch dams. It is evident that the seismic waves may reach on the dam site from any direction. Therefore, this study considers the seismic waves arrive to the dam site with different angles, ${\theta}=0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$, and $90^{\circ}$ for non-linear analysis of arch dam-water-foundation interaction system. The N-S, E-W and vertical component of the Erzincan earthquake, on March 13, 1992, is used as the ground motion. Dam-water-foundation interaction is defined by Lagrangian approach in which a step-by-step integration technique is employed. The stress-strain behavior of the dam concrete is idealized using three-dimensional Drucker-Prager model based on associated flow rule assumption. The program NONSAP is employed in response calculations. The time-history of crest displacements and stresses of the dam are presented. The results obtained from non-linear analyses are compared with that of linear analyses.

• 자연, 터널 그리고 지하공간
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• 제21권2호
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• pp.117-129
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• 2019

Tunnelling in urban environments is very common nowadays as large cities are expanding and transportation demands require the use of the underground space for creating extra capacity. Inevitably, any such new construction may have significant effects on existing nearby infrastructure and therefore relevant assessment of structural integrity and soil-structure interaction is required. Foundation piles can be rather sensitive to nearby tunnel construction and therefore their response needs to be evaluated carefully. Although detailed three-dimensional continuum finite element analysis can provide a wealth of information about this behaviour of piles, such analyses are generally very computationally demanding and may require a number of material and other model parameters to be properly calibrated. Therefore, relevant simplified approaches are used to provide a practical way for such an assessment. This paper presents a simple method where the pile is modelled with beam finite elements, pile-soil interaction is modelled with soil springs and tunnelling-induced displacements are introduced as an input boundary condition at the end of the soil springs. The performance of this approach is assessed through some examples of applications.

• Coupled systems mechanics
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• 제11권5호
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• pp.373-387
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• 2022

In this paper,soil-structure interaction effects on the seismic response of multistory frame structure on raft foundation are numerically analyzed. The foundation soil profile is assumed to consists of a clay layer of variable thicknessresting on bedrock. Amodified plane-strain numerical model isformed in the software Plaxis, and both free vibration analysis, and earthquake analysis for a selected ground motion accelerogram are performed. The behavior of the structure is assumed to be linear elastic with Rayleigh viscous damping included. The behavior of the clay layer is modeled with a Hardening soil model with small strain stiffness. The computed results in terms of fundamental period and structural horizontal displacementsfor the case of fixed base and for different thicknesses of clay layer are presented, compared, and discussed.

• Earthquakes and Structures
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• 제24권3호
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• pp.165-181
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• 2023

The effectiveness of fluid viscous dampers (FVDs) on dynamic response mitigation of coupled two adjacent structures was investigated, considering soil-structure interaction (SSI) effects under earthquake excitation. A numerical procedure was employed to evaluate system response. The finite elements were used for the numerical treatment of the adjacent buildings and soil region. Viscous boundary conditions were used as special non-reflecting boundaries on the edges of finite soil region. According to the results, the FVDs were found to be very effective for dynamic response mitigation of the adjacent buildings, even if considering the soil medium. The results showed that the most affecting parameter on the system response was found to be soil type. It was also concluded that when adjacent structures coupled by FVDs, the maximum values of the roof displacements, the base shear forces, and the base bending moments could decrease up to around 50%. Changing in lateral stiffness of the one building has minor effects on the effectiveness of viscous dampers.

• 풍력에너지저널
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• 제2권1호
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• pp.61-67
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• 2011

In the present study, numerical unsteady simulations of the NREL Phase VI wind turbine in downwind operation conditions were conducted to investigate rotor-tower interaction. The calculations were performed using an unstructured mesh, incompressible Reynolds-averaged Navier-Stokes flow solver. To capture the unsteady effects associated with the tower shadow between the rotor blades and the tower, the wind turbine was modelled including the rotor, tower, hub, and nacelle. The present results generally showed good agreements with available experimental data. At the lowest wind speed, the pressure distribution was characterized by a complete collapse of the suction peak on the blade when the blade passes through the tower wake. It was found that unsteady effects play a significant role in the response of the blades.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.322-331
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• 2016

본 연구는 청소년의 분노에 대해 자아존중감과 자아탄력성이 미치는 영향과 함께 상호작용 효과를 탐색하고 분노에 대한 지도방안을 도출하는 것을 목적으로 하였다. 이를 위해 419명의 청소년을 대상으로 분노, 자아존중감, 자아탄력성을 측정하였다. 수집된 자료는 다중회귀분석과 위계적회귀분석을 사용하여 분석하였고, 그결과는 다음과 같다. 첫째, 청소년의 분노 수준은 자아탄력성의 하위요인인 감정조절과 흥미와 관심의 다양성, 자아존중감의 하위요인인 학교에서의 자아존중감이 부적 영향을 주었다. 둘째, 분노억제는 자아 존중감의 하위요인인 학교에서의 자아존중감과 사회적 자아존중감, 자아탄력성의 하위요인인 감정조절이 부적 영향을 주었다. 셋째, 분노 조절은 자아탄력성의 하위요인인 감정조절과 자아존중감의 하위요인인 가정에서의 자아존중감이 정적 영향을 주었다. 넷째, 분노 수준에 대한 자아존중감과 자아탄력성의 상호작용 효과는 통계적으로 유의한 것으로 나타났다. 마지막으로 분노 조절에 대한 자아존중감과 자아탄력성의 상호작용 효과는 통계적으로 유의한 것으로 나타났다.

• 도시과학
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• 제6권2호
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• pp.59-72
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• 2017

Studies on the calculation of accident costs include the approach on calculating damage costs covering all accidents regardless of first or secondary party and the one calculating damage costs generated by a single victim. These two approaches have a limitation of considering a subject for costs analysis as a single entity. In addition, research on estimating the interaction effects caused in the relationship between diverse traffic accident features and factors remains inadequate since most studies focused on calculating costs incurred in a single entity such as a victim, damaged building, or social organization in charge of managing car accident. This study intends to identify the expected range of old age where a specific interaction effect would remain, compare accidents between old age section and the entire age section, and discover an exogenous variable to be applied in accident drop effects in senior people and reduced benefits by calculating and testing additional accident costs in case the first party and the second party all pertain to the senior age section. By classifying the entire accidents caused by old drivers according to the types of cars, significant coefficients representing the influence that affects car accidents according to the characteristics are calculated and set them as the representative variables by selecting top variable in accordance with from low to high order. Furthermore, characteristics on five age groups such as a group of over 65 and less than 70, a group of over 70 and less than 75, a group of over 75 and less than 80, a group of over 80 and less than 85, and a group of over 85 are elicited and compared them with these preselected accident characteristics variables, thereby identifying what changing effects come out.

• 한국연소학회지
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• 제18권4호
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• pp.29-36
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• 2013

Numerical study was conducted to clarify effects of added $CO_2$ for the downstream interaction between $H_2$-air and CO-air premixed flames in counterflow configuration. The reaction mechanism adopted was Davis model which had been known to be well in agreement with reliable experimental data. The results showed that both lean and rich flammable limits were reduced. The most discernible difference between the two with and without having $CO_2$ addition into $H_2$-air and CO-air premixtures was two flammable islands for the former and one island for the latter at high strain flame conditions. Even a small amount of $H_2$, in which $H_2$-air premixed flame cannot be sustained by itself, participates in CO oxidation, thereby altering the CO-oxidation reaction path from the main reaction route $CO+O_2{\rightarrow}CO_2+O$ with a very long chemical time in CO-air flame to the (H, O, OH)-related reaction routes including $CO+OH{\rightarrow}CO_2+H$ with relatively short chemical times. This intrinsic nature alters flame stability maps appreciably. The results also showed that chemical effects of added $CO_2$ suppressed flame stabilization. Particularly this phenomenon was appreciable at flame conditions which lean and rich extinction boundary was merged. The detailed discussion of chemical effects of added $CO_2$ was addressed to the present downstream interaction.

• 한국컴퓨터산업학회논문지
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• 제5권2호
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• pp.193-202
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• 2004

본 연구는 인터넷기반 실습 수업에서 교수자와 학습자가 어떠한 방식으로 교수-학습 상호작용 활동을 수행하는 방식과 웹기반 실습 수업의 교육적 효과에 관하여 연구하였다. 산업체 재직자의 정보화교육을 지원하는 "전자상거래 시스템 구축" 교육과정에서 교수자와 학습자는 어떤 방식으로 교수-학습 및 상호작용 활동을 수행하는지, 웹기반 실습교육의 효과는 무엇인지를 살펴보고자 하였다. 연구대상은 산업체 직장인 및 기타 25인에 대하여 1학기에 걸쳐서 이루어졌으며, 연구방법으로는 학습결과 프로파일 분석, 설문조사, 인터뷰 등을 사용하였다. 연구결과 학습자-교수자-운영자간 상호작용은 활발하게 이루어지지 않았으나 학습자의 관심, 이메일 사용, 게시판 질의 및 응답, 온라인 실습 등의 강의 방식이 학습자의 상호작용 및 교육효과에 영향을 미치는 것으로 나타났다. 것으로 나타났다.