• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.977-981
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• 2002

The ordinary differential equations governing free vibrations of elastic horizontally curved beams are derived, in which the effect of shear deformation as well as the effects of vertical, rotatory and torsional inertias are included. Frequencies and mode shapes are computed numerically for parabolic curved beams with the hinged-hinged, hinged-clamped and clamped-clamped ends. Comparisons of natural frequencies between this study and ADINA are made to validate the theories and numerical methods developed herein. The lowest three natural frequency parameters are reported, with and without the effect of shear deformation, as functions of the three non-dimensional system parameters: the horizontal rise to span length ratio, the slenderness ratio and the stiffness parameter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1000-1005
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• 2010

Ride comfort is an important factor for the development of a high-speed train. The aerodynamic force to a high speed train inside tunnels increases the car-body vibration and makes its ride comfort worse. In this study, the aerodynamic force is estimated through a CFD analysis using ADINA, and its car-body vibration and ride comfort are calculated for the aerodynamic force which acts on the side of the train. The numerical results show that the vibration is a lateral mode of the car-body and decreases the ride comfort. On the basis of this numerical simulation, more accurate simulation is necessary for the shape of tunnel and the lateral suspension system of a high speed train.

• 한국소음진동공학회논문집
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• 제13권1호
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• pp.63-69
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• 2003

The ordinary differential equations governing free vibrations of elastic horizontally curved beams are derived, in which the effects of rotatory inertia and shear deformation as well as the effects of both vertical and torsional inertias are included. Frequencies and mode shapes are computed numerically for parabolic curved beams with the hinged-hinged, hinged-clamped and clamped-clamped ends. Comparisons of natural frequencies between this study and ADINA are made to validate the theories and numerical methods developed herein. The lowest three natural frequency parameters are reported. with and without the effects of rotatory inertia and shear deformation. as functions of the three non-dimensional system parameters: the horizontal rise to span length ratio. the slenderness ratio and the stiffness parameter.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.137-142
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• 1992

The purpose of this study is to develop a new structural system for precast deck plate bridge. In order to investigate load distribution and composite effects by connecting diaphragms and precast deck plate to main girder with shear keys, computer analysis with F.E.M S/W package program ADINA was carried out. As results of analysis, the following could be concluded : -The distance between diaphragms with6m is suficient for crossing load distribution effects. -The composite effects by connection deck plate to main girder with shear key is reasonable. -The gap between deck plate and main girder under given load is negligible.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.43-50
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• 2022

The students' feedback is important to measure and improve teaching performance. Many teacher performance evaluation systems are based on responses to closed question, but the free text answers can contain useful information which had to be explored. In this paper we present a lexicon-based sentiment analysis to explore students' text feedback. The data was collected from a system for the evaluation of teachers by students developed and used in our university. The students comments are in Romanian language so we built a Romanian sentiment word lexicon. We used this to categorize the feeback text as positive, negative or neutral. In addition, we added a new polarity - indifferent - in order to categorize blank and "I don't answer" responses.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1108-1118
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• 2009

A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

• Structural Engineering and Mechanics
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• 제37권3호
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• pp.309-320
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• 2011

As a new type of large-span space structure, suspendome is composited of the upper single-layer reticulated shell and the lower cable-strut system. It has better mechanical properties compared to single-layer reticulated shell, and the overall stiffness of suspendome structure increases greatly due to the prestress of cable. Consequently, it can cross a larger span reasonably, economically and grandly with high rigidity, good stability and simple construction. For a better assessment of the advantages of mechanical characteristic of suspendome quantitatively, the static behavior of Kiewitt6 suspendome was studied by using finite element method, and ADINA was the software application to implement the analysis. By studying a certain suspendome, the internal forces, deformation and support constrained forces of the structure were obtained in this paper. Furthermore, the influences of parameters including prestress, stay bar length, cross-sectional area and rise-to-span ratio were also discussed. The results show that the increase of prestress and vertical stay bar length can improve the stiffness of suspendome; Cross-sectional area has nearly no impact on the static behavior, and the rise-to-span ratio is the most sensitive parameter.

• 한국지반공학회논문집
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• 제27권6호
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• pp.27-37
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• 2011

최근 가압 그라우팅 형식의 약액주입공법이 지반의 지반개량, 차수, 강도 증대 등의 목적으로 널리 쓰이고 있다. 이에 지반조건에 따른 고결체의 크기 및 형상을 측정하여 적정 주입압 및 주입시간을 정하는 것은 경제적이고 합리적인 시공을 위해 필수적이다. 그러나, 현장에서 시험시공을 통한 고결체 채취는 시간과 비용이 많이 소모되며, 그라우팅 공법을 적용한 지반에 고결체의 크기와 형상을 예측한 시스템은 현재까지 없다. 따라서, 본 연구에서는 물유리계 약액을 사용하여 주입압(50kPa, 100kPa, 150kPa)에 따른 실내모형주입시험을 실시하고 이를 전산유체역학(CFD)의 porous media모델과 VOF(Volume of Fluid) 기법을 이용한 수치해석을 실시하여 비교 분석하였다. 수치해석 결과, VOF 기법을 이용한 주입모사는 지중 속에 주입된 가압 그라우팅의 거동 및 고결 양상을 예측할 수 있는 기초적인 수치해석적 기법이 될 것으로 판단된다.