• Title, Summary, Keyword: 이동하중

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Dynamic Analysis of Catenary System Subjected to Moving Load (이동하중을 받는 일정장력이 작용하는 가선계의 동적해석)

  • Lee, Kyu-Ho;Cho, Yong-Hyun;Chung, Jin-Tai
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.1
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    • pp.99-106
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    • 2011
  • In this study, the dynamic contact of a catenary system is analyzed by using the finite element method. We derive the equations of motion for the catenary system by taking into consideration tension on the catenaries. After establishing the weak form, they are spatially discretized with beam elements. Then, we analytically calculated the wave propagation speed for a string, bar, beam, and the catenaries subjected to tension. Further, finite element computer program for contact dynamic analyses is developed. Finally, we analyze the wave propagation response corresponding to the moving load to the contact line are calculated.

Investigation of Impact Factor and Response Factor of Simply Supported Bridges due to Eccentric Moving Loads (이동하중의 편측재하에 따른 단순교의 충격계수 및 응답계수 변화 분석)

  • Hong, Sanghyun;Roh, Hwasung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.105-113
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    • 2018
  • The proposed model to predict the bridge load carrying capacity uses the impact response spectrum. The spectrum is based on Euler-Bernoulli beam and the center of the bridge width for the moving load location. Therefore, it is necessary to investigate the eccentric moving load effects on the impact factor and response factor. For this, this study considers 10 m width and two-lane simply supported slab bridges and performs the moving load analysis to investigate the variations of peak impact factor and corresponding response factor. The numerical results show that the eccentric load increases both the static and dynamic displacements, but the impact factor is decreased since the incremental amount of static displacement is bigger than that of dynamic displacement. However, the difference of the impact factors between the center and eccentric loadings is small showing less than 0.5%p. In the response factor, the eccentric loading increases both the static and dynamic response factors, compared to the center loading. The difference of the response factor is only 0.18%p. It shows that the eccentric loading has very small effects on the response factor, thus the impact factor response spectrum which is generated based on the center moving load can be used to determine the response factor.

Vibrational Characteristics of Buried Gas Pipelines under Train Moving Loads (열차 이동하중에 의한 지중 매설 가스 배관의 진동 특성)

  • Won, Jong-Hwa;Kim, Moon-Kyum;Sun, Jin-Sun;Kim, Mi-Seung;Dang, N.Hai
    • Journal of the Korean Institute of Gas
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    • v.13 no.1
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    • pp.1-8
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    • 2009
  • Recently, the vibration of underground structure due to high speed railway loads has been increased substantially as compared with middle and slow speed. The buried gas pipelines under continuous impact forces and repeated loading are more influenced by the vibrational loads than another pipelines. However, the static analysis was not enough to allow for the effect of vibrations because it uses impact factors for the design or analysis process. In this study, characteristics of Pipelines was quantitatively estimated through each conditions of soil covers and train speed, and the new vibration prediction is presented about the vibrational velocity.

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Improvement on Geomorphic Changes of Water Intakes at Haepyeng by Numerical Simulation (수치모의를 이용한 해평취수장의 취수장애 개선 연구)

  • Jang, Chang-Lae;Lee, Kwang-Man
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.373-377
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    • 2007
  • 본 연구는 하천수를 직접 취수하는 기존 취수장의 취수장애 문제를 해결하기 위한 대안을 개발하는데 목적이 있다. 이를 위해 지금까지 취수장 문제해결 방법으로 검토되지 않았던 유로(流路) 및 하천의 지형변동을 GIS 및 항공사진을 이용하여 정량적으로 파악하였으며, 유사영역 구분 및 하도특성 분석, 하천 특성 해석에 적합한 이동경계 좌표계를 이용한 수치모형을 적용하여 2차원 하상 및 지형변동 예측을 검토하였다. 저수로의 이동 및 하상저하로 인하여 취수문제가 발생하고 있는 경상북도 구미시에 위치한 해평취수장 주변에 대하여 항공사진 분석 및 GIS 기법을 이용하여, 시간 경과에 따른 하천 형태 변화 저수로의 이동 특성을 조사하고 분석하였다. 저수로는 좌안에서 우안으로 이동해 가고 있으며, 이는 하천의 경사가 급하고 하폭이 증가하면서 발생하는 현상으로 저수로의 불안정성이 크게 증가 하는 특성을 보여주었다. 시간의 증가에 따라 저수로 하폭의 증가율이 감소하고 있으며, 수로의 측방 이동을 보여주고 있으며, 시간이 증가함에 따라 측방향 이동율이 감소하였다. 만재유량을 이용하여 유사의 영역구분을 수행한 결과, 망상하천으로서, 모래하천으로 부유사가 지배적인 하천으로 판단되었다. 2차원 수치모형을 이용하여 하상변동을 모의한 결과, 유량이 $2,000\;m^3/s$일 경우에는, 해평 취수장 측의 하천 하상은 상승하였으며, 구미정수장 측에서는 하상이 저하되었다. 홍수유량 $8,000\;m^3/s$일 경우에는 해평 취수장 측에서는 약간 저하하였고, 구미정수장 측에서는 하상이 상승하나, 직하류에서는 하상이 세굴되고, 하천 가운데 자리하고 있는 하중도는 커지는 현상을 보여 주었다. 또한 하중도 직하류에서는 하중도를 중심으로 좌안인 해평 취수장과 우안인 구미정수장 쪽으로 분류된 흐름이 합류되면서 하상에서는 퇴적과 세굴이 반복되며, 복렬 사주가 발생하는 것으로 나타났다. 이는 두 흐름에 의해 와(vortex)가 크게 형성되어 하상의 세굴에 영향을 미치기 때문으로 판단되었다.

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A Study on the Blind Type of Waterproofing Layer of Wheel Tracking of Test Method and Valuation on Working of Live Load (이동하중이 작용하는 비노출 방수층의 윤하중 시험방법 및 평가에 관한 연구)

  • Eom Deok-Jun;Seon Yun-Suk;Kwon Si-Won;Oh Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.1-5
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    • 2005
  • There are a lot of problem about waterproofing membrane coating for concrete deck of bridge and waterproofing sheets for concrete of deck of bridge because it couldn't confirm waterproofing's defeat after construction. These problems make a waterproofing material damage and concrete deck of bridge damage. So It needs a lot of money for repair work and reinforcement work. Therefor the structure slab of using waterproofing material protect invasion of water. Also, Concrete deck of bridge need a endurance permeability for the reduction repair payment. In this study, An experimental study on the quality standardization test method waterproofing layer on working of live load

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Usage of Dynamic Vibration Absorbers for a Beam Subjected to Moving Forces and for a System Mounted on a Moving Base (이동하중을 받는 보와 가동 기초 위에 설치된 계에의 동흡진기의 이용)

  • Lee, Gun-Myung;Byun, Jai-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.6
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    • pp.27-34
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    • 2015
  • Dynamic vibration absorbers are widely used in machinery, buildings, and structures, including bridges. Two cases of their usage are considered in this paper. One is a simply supported beam subjected to either a moving force or a sequence of moving forces, which simulates a train-bridge interaction problem. The other is a case where a primary system is mounted on a base that is not grounded and is excited by an external force. The conditions that the dynamic vibration absorbers must meet in these cases are found and compared to those for usual cases where bases of primary systems are grounded.

Vibration Analysis of Multi-Span Timoshenko Beams Due to Moving Loads (여러 스팬을 갖는 티모센코 보 구조물의 이동하중에 의한 진동 해석)

  • Hong, Seong-Uk;Kim, Jong-Uk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.11
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    • pp.2058-2066
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    • 1999
  • The present paper proposes a new dynamic analysis method for multi-span Timoshenko beam structures supported by joints with damping subject to moving loads. An exact dynamic element matrix method is adopted to model Timoshenko beam structures. A generalized modal analysis method is applied to derive response formulae for beam structures subject to moving loads. The proposed method offers an exact and closed form solution. Two numerical examples are provided for validating and illustrating the proposed method. In the first numerical example, a single span beam with multiple moving loads is considered. A dynamic analysis on a multi-span beam under a moving load is considered as the second example, in which the flexibility and damping of supporting joints are taken into account. The numerical study proves that the proposed method is useful for the vibration analysis of multi-span beam-hype structures by moving loads.

A Moving Track Test Using Tire-Wheel Tracking Machine (고무바퀴트랙하중 시험기를 이용한 왕복하중실험)

  • Sung, Ik-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.250-256
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    • 2010
  • In this paper, an analytical and experimental study is performed in order to determine the effects of interaction between vehicle and bridge superstructure. For this purpose an improved wheel tracking machine and an adequate single span bridge are designed. Results presented in the paper show that wheel tracking machine including moving mass effects can demonstrate more accurate dynamic interaction between vehicle and structure.

Robust Trajectory Tracking Control of a Mobile Robot Based on Weighted Integral PDC and T-S Fuzzy Disturbance Observer (하중 적분 PDC와 T-S 퍼지 외란 관측기를 이용한 이동 로봇의 강인 궤도 추적 제어)

  • Baek, Du-san;Yoon, Tae-sung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.2
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    • pp.265-276
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    • 2017
  • In this paper, a robust and more accurate trajectory tracking control method for a mobile robot is proposed using WIPDC(Weighted Integral Parallel Distributed Compensation) and T-S Fuzzy disturbance observer. WIPDC reduces the steady state error by adding weighted integral term to PDC. And, T-S Fuzzy disturbance observer makes it possible to estimate and cancel disturbances for a T-S fuzzy model system. As a result, the trajectory tracking controller based on T-S Fuzzy disturbance observer shows robust tracking performance. When the initial postures of a mobile robot and the reference trajectory are different, the initial control inputs to the mobile robot become too large to apply them practically. In this study, also, the problem is solved by designing an initial approach path using a path planning method which employs $B\acute{e}zier$ curve with acceleration limits. Performances of the proposed method are proved from the simulation results.

원자로 냉각재 배관용 SA516-Gr.70 강의 파괴저항성에 미치는 온도 및 하중속도의 영향

  • 윤지현;이봉상;오용준;김진원;홍준화
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.48-53
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    • 1998
  • 원자력 발전소 배관계통에 파단전 누설 (LBB) 설계개념의 적용을 위해서는 원자로 가동온도에서의 재료의 파괴저항성 평가가 필수적이다. 본 연구에서는 국내 원자로의 1차 냉각계통배관의 엘보우 소재로 사용되는 SA516-Gr.70 강의 파괴저항성에 미치는 DSA (Dynamic Strain Aging, 동적변형시효) 영향을 고찰하였다. 파괴저항성 평가를 위해 원자로 가동온도를 포함한 상온~50$0^{\circ}C$ 온도영역에서 준정적 하중에서부터 지진 하중 정도의 동적 하중까지 하중속도를 달리하여 직류전위차법 (DCPD) 이용하여 J-R 시험을 행하였다. J-R 시험결과, SA516-Gr.70 강은 특정한 온도와 하중속도의 조합에서 파괴저항성이 크게 떨어지는 양상을 보였으며, 낮은 파괴저항성을 나타내는 온도는 하중속도가 증가함에 따라 높은 온도쪽으로 이동하는 전형적인 DSA 감수성을 보였다. 인장시험을 통해서도 큰 폭의 serration 이 관찰되었으며 SA516-Gr.70 강에서 파괴저항성의 변화와 DSA 현상과의 연관성을 고찰하였다.

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