• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.629-638
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• 1999

본 연구에서는 고속철도에서 차량·교량 구조물의 상호작용을 가능한 정밀하게 취급할 수 있는 3차원 해석모형을 개발하였다. 경부고속철도 교량형식인 PSC 박스거더 교량을 40m 단순 와 25-40-25m 3경간 연속 에 대해 뼈대요소를 사용하여 3차원으로 모형 하였으며, 궤도의 불규칙성은 정상확률과정으로 가정하고, 지수 스펙트럼 밀도함수를 사용하여 궤도의 형상을 생성시켰다. 열차는 경부고속철도 차량 하중효과가 가장 큰 동력차 만을 대상으로 17 자유도 모형과 38 자유도 모형으로 분리하여 개발하였다. 다양한 조건에 대한 분석결과를 검토하면 여러 가지 상황에서 38 자유도 모형의 필수 성이 보여지고 있다. 특히 교량의 솟음 및 장기 처짐에 의한 궤도형상변화가 있는 경우에는 반드시 38 자유도 모형이 적용되어야 하는 것으로 분석되었다. 또한 제동하중이 작용할 때 쏠림 효과에 의한 영향이 큰 것으로 평가되어, 제동에 의한 교량의 동적 거동은 종변 위에 대한 자유 도를 고려할 수 있는 주행차량모형으로 해석되어야 함이 규명되었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.151-160
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• 2006

In this study, we propose a new efficient 2-noded hybrid-mixed element for curved beam vibrationshaving a uniform and non-uniform cross section. The present element considering transverse shear strain is based on Hellinger-Reissner variational principle and introduces additional nodeless degrees for displacement field interpolation in order to enhance the numerical performance. The stress parameters are eliminated by the stationary condition and then the nodeless degrees are condensed out by the Guyan reduction. In the performance evaluation process of the present field-consistent higher-order element, we carefully examine the effects of field consistency and the role of higher-order interpolation functions on the hybrid-mixed formulation. Several benchmark tests confirm e superior behavior of the present hybrid-mixed element for curved beam vibrations.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.3 s.18
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• pp.11-21
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• 2005

This study is performed to understand complex behavior and to investigate the rational analysis methods for seismic design of the curved bridges. To analyze the curved bridges for the seismic loadings, it is used that the finite element analysis program has the 7-dof curved beam and straight beam element. The free vibration characteristics of the curved bridges are compared with the straight bridges that have span length same as the average arc length of inside and outside girder of those. For the same case, the dynamic behavior is compared under seismic loadings. It is found that regular bridges classified by AASHTO are analyzed as if those were straight. To investigate the dynamic behavior of general curved bridges under seismic loading, the seismic loading directions and the subtended angle of curved bridges are varied.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.4
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• pp.290-295
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• 2001

Subsets pipelines are exposed to several potential risks of damage due to corrosion, soil instability, anchor impact and other hazards. One of the main risk factors for the safety of a subsea pipeline is its free spanning. This paper examines the safety of subsea pipelines with free span under axial compressive load. The variation of allowable lengths of dynamic free span is examined for generalized boundary conditions. The free span is modelled as a beam with an elastic foundations and the boundary condition is replaced by linear and rotational springs at each end. A dynamic free span curve is obtained with a function of non-dimensional parameters and can be used usefully for the design of subsea pipelines with a free span. A case study is carried out to introduce the application method of the curve.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.398-403
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• 1996

이 논문에서는 지반과 기초를 일반적인 3차원 유한요소로 모델링하고, 유한요소의 바깥영역은 일반적인 모드의 축대칭 유한요소와 축대칭 Hyperelement를 사용하여 전달경계로 모델링하여, 유한요소와 전달경계의 경계에서 두 요소간의 연계에 의하여 기초에서의 동적강성행렬을 구한다. 이를 위하여 3차원 유한요소와 축대칭 요소간의 연계방법을 제안한다. 제시되는 기초의 동적강성행렬은 x,y,z방향의 병진성분과 x,y,z축에 관한 회전성분의 6자유도로 표현된다. 이 논문에서 사용한 3차원 유한요소와 축대칭 요소의 연계 방법의 검증을 위하여 구형기초와 등가의 강성을 갖는 강체원형기초의 동적강성행렬을 구하고 이를 비교하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.3
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• pp.1-9
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• 2011

The purpose of this study is to examine the dynamic characteristics of low, medium and high speed Maglev trains and guideways through dynamic interaction analysis. The coupled dynamic equations of motion for a vehicle of 10-dof and the associated guideway girders are developed by superposing vibration modes of the girder itself. The controller used in the UTM-01 Maglev vehicle is adopted to control the air gap between the bogie and guideway in this study. The effect of roughness, the guideway deflection-ratio and vehicle speed on the dynamic response of the maglev vehicle and guideway are then investigated using the 4th Runge-Kutta method. From the numerical simulation, it is found that the air gap increases with an increase of vehicle speed and the roughness condition. In particular, the dynamic magnification factor of the guideway girder is small at low and medium speeds, but the factor is noticeable at super-high speeds.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.793-802
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• 2002

This study presented a finite element formulation for the dynamic analysis of horizontally curved I-girder bridges. The stiffness and mass matrices of the curved and the straight beam elements are formulated. Each node of both elements has seven degrees of freedom, including the warping degree of freedom. The curved beam element is derived from Kang and Yoo's theory of thin-walled curved beams. The computer program EQCVB has been developed to perform dynamic analyses of various horizontally curved I-girder bridges. The Gupta method is used to solve the eigenvalue problem efficiently, while the Wilson-${\theta}$ method is used for the seismic analysis. The efficiency of EQCVB is demonstrated by comparing solution time with ABAQUS. Using EQCVB, the study is applied to investigate the dynamic behavior of horizontally curved I-girder bridges under seismic loading.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1439-1446
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• 1991

본 연구에서는 동적영향계수의 축차전달에 그 개념을 두고 있는 전달영향계수 법을, 2층 원판구조물의 자유진동해석애 적용해서, 그 알고리즘을 정식화 하고 전달매 트릭스법과 비교 검토하였다.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.797-803
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• 2010

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of pre-stressed concrete (PSC) box girder bridges on the Korea high speed railway. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyze accurately and evaluate with in-depth parametric studies for dynamic responses of bridge due to the high speed railway vehicles. Three dimensional frame element is used to model the PSC box girder bridges, simply supported span lengths 40 m. The high-speed railway vehicles (K-TGV) including a locomotive are used as 38-degree of freedom system. Three displacements (vertical, lateral, and longitudinal) as well as three rotational components (pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic analysis by Runge-Kutta method which are able to analyze considering the dynamic impact factors are compared and contrasted. It is proposed as an empirical formula that the impact factors damaged the bridge load-carrying capacities occurs to the bride due to high-speed vehicle.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.75-85
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• 2000

When applying a system identification technique, which incorporates an experimental model to a corresponding finite element model of a structure, one of the major problems is the large difference in the numbers of degrees of freedom (dof) between the two models. While there are large number of dofs in a finite element model, the number of measurement points is practically limited. So it is very difficult to incorporate them. Especially rotational dofs are hard to measure. In this study a method is presented for estimating structural dynamic responses at unmeasurable locations in frequency domain. The proposed method is tested numerically and the feasibility for practical application has been demonstrated through an example structure under moving loads, where translational and rotational dofs of beam at a center point are estimated from the partial measurements of responses at accessible points.