• Title/Summary/Keyword: Moving wall

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Eco-Moving Wall for a Preventing Floods using Glass Fiber Reinforced Composite (유리섬유복합소재를 이용한 지중매설형 승하강식 홍수방지 벽체구조물)

  • Yun, Youngman
    • Journal of the Society of Disaster Information
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    • v.9 no.4
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    • pp.462-468
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    • 2013
  • Walls for preventing floods using overturning or buoyancy method have been developed as replacement construction for preventing floods in and outside country. However, as they have some problems with pre-inspection and maintenance control, Eco-moving wall structure for preventing floods was studied and first developed using Glass Fiber Reinforced Composite which has not only light weight but outstanding strength. The developed wall structure for preventing floods offering structural stability and field applicability through numerical analysis was confirmed to reduce construction expenses by around 87~95% and secure waterproof property with the inside of the wall installed rubber water stopper.

Development of Gondola-type Building Management Robot Platform and Mechanism for Moving/Tasking on Building Outer-wall (곤돌라형 외벽 유지관리 로봇의 이동/작업 메커니즘 및 플랫폼 개발)

  • Ham, Young-Bog;Park, Soung Jea
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.4
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    • pp.375-382
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    • 2013
  • Down through the years, human needs and desires have required a robot system to work at hazardous environments instead. Current painting task is costly and laborious, and it exposes workers to significant health and safety risks. Automation system offers potential improvement in this area and is especially well suited to the outer-wall painting tasks in concrete structures. This paper introduces the result of gondola-type building management robot(G-BMR) platform and mechanism for moving/tasking on building outer-wall for the outer-wall painting. Its technical and economic feasibility are conducted, and it is concluded that developing G-BMR is physically and economically feasible in this research. And we discuss about the future of G-BMR and automation in construction field.

Analysis of Pulsating Flow in Elastic Parallel Plates and an Elastic Pipe Model Using Moving Boundary Algorithm (이동경계 수치해법을 이용한 탄성평판 및 탄성관 모델내의 맥동유동 해석)

  • Park Hyung Gyu;Kim Charn-Jung;Lee Chong-Sun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.4 s.235
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    • pp.425-434
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    • 2005
  • In order to analyze pulsating flows in elastic blood vessels, a method based on the ALE concept and finite volume method was reformed and modulated to include wall motion of elastic vessels and impedance phase angle(phase difference between wall motion and blood flow). Our study indicated wall shear rates(WSR) were significantly influenced by the wall motion and the impedance phase angle. For larger wall motion more than $5{\%},$ the computed WSR started to deviate from the results of the perturbation theory that assumed smaller wall motion. The study showed that oscillatory shear index increased as the impedance phase angle became more negative like $-70{\circ}\;or\;-80{\circ}$ due to reduced mean WSR and increased amplitude of WSR. This result indicated that hypertensive patients are more vulnerable to atherosclerosis than normal persons because of the role of more negative impedance phase angles usually observed in these patients.

Evaluation of Dynamic Stability for Structural Bar Reinforced Precast and Prestressed Retaining Wall for Moving Train Load (이동열차하중에 대한 강봉으로 보강된 프리캐스트 프리스트레스트 옹벽의 동적 안정성 평가)

  • Lee, Il Wha;Um, Ju Hwan;Lee, Kang Myung;Keum, Chang Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.190-198
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    • 2011
  • The precast production has many advantages by fast construction period, labor-saving and high quality. In recent years, the application of the precast product has been increased in the earth retaining wall field. This paper presents the results of the numerical analysis that was carried out to evaluate the dynamic stability of precast and prestressed earth retaining wall under moving train load. The two-dimensional FEM analysis was used to the numerical analyses. The train load to act on trackbed is combined by the real measured roughness phase angle and quasi-static load. The dynamic stability is analysed by the displacement, acceleration and stress under moving train load at each specified location. The results of the analysis show that the precast and prestressed retaining wall has very stable capability for the railway.

Performance Analysis of Moving Bed Heat Exchanger of Solid Particles in a Vertical Pipe (고체입자 이동층을 이용한 수직 전열관 열교환기의 성능해석)

  • Park, Sang-Il;Choe, Gyeong-Bin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.9
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    • pp.2916-2923
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    • 1996
  • A numerical analysis of the moving bed heat exchanger of solid particles inside the vertical pipe was performed using finite difference method. Also, the theoretical solutions were obtained for comparison when the wall heat flux or the wall temperature was assumed constant. The comparison showed that their results agreed well each other. The moving bed heat exchanger was classified as countercurrent-flow, parallel-flow, and cross-flow types according to the gas flow direction. For each type, the thermal efficiency of heat exchanger was calculated as a function of non-dimensional parameters such as the characteristic length of heat exchanger, Biot number and the ratio of thermal capacities of gas and solid particles.

Heat Transfer of Oscillating Flow in a Cylinder with Regenerator (재생기를 가진 실린더내의 왕복유동에 관한 열전달)

  • 김진호;이재헌;강병하
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.7
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    • pp.1758-1769
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    • 1995
  • The heat transfer of oscillating flow in a cylinder with regenerator was investigated by the moving boundary technique. The flow in regenerator was modeled by means of Brinkman Forchheimer-Extended-Darcy equation . Results showed that when piston moved toward right, velocity vectors near cylinder wall at left piston and right side of regenerator inclined to symmetric axis and velocity vectors near cylinder wall at right piston and left side of regenerator inclined to cylinder wall. And the time averaged Nusselt number was increased by 46.73% when the oscillatory frequency became twice and decreased by 31.46% when the oscillatory frequency became half. The time averaged Nusselt number was increased by 18.09% when thickness of the regenerator became twice and decreased by 7.53% when thickness of the regenerator became half. But mesh size of regenerator hardly affected the Nusselt number. And efficiency of regenerator was larger as the oscillatory frequency was smaller, thickness and mesh size of regenerator was larger.

A Numerical Study on the Flow Characteristics of a Peristaltic Micropump (연동형 마이크로펌프의 유동에 대한 수치해석 연구)

  • Lee, Na-Ri;Lee, Sang-Hyuk;Hur, Nahm-Keon
    • The KSFM Journal of Fluid Machinery
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    • v.12 no.4
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    • pp.37-43
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    • 2009
  • In the present study, the flow characteristics of a peristaltic micropump were numerically analyzed. A channel wall motion of the micropump was simulated using a moving mesh technique. A sine wave pattern was assumed to simulate the peristaltic motion of wall. The present numerical method was verified by comparing the result with the available numerical data. The effects of the operating conditions which include the maximum displacement and frequency of the channel wall and the phase difference between top and bottom walls on the flow characteristics were investigated. From these numerical results, the pressure-flowrate characteristic curve was obtained for various maximum displacement and frequencies.