• Title/Summary/Keyword: Dynamic interaction

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Dynamic Responses of a Slender Offshore Structure Subject to Level Ice Load (平坦氷荷重을 받는 細長形 해양구조물의 動的 거동)

  • Choi, Kyung-Sik
    • Journal of Ocean Engineering and Technology
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    • v.9 no.2
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    • pp.156-166
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    • 1995
  • Regrading the development of offshore natural gas field near Sakhalin Island which is an ice-infested area, this study aims to estimate the dynamic ice load for construction of offshore structures operating in this region. In this paper the design ice load and dynamic responses of a slender Arctic structure upon continuous ice movement are sutdied. Crushing agter a certain elastic deformation is assumed as a primary failure mechanism at the contact zone between semi-infinite level ice edge and the face of structure. Dynamic interaction forces are calculated using a modified Korzhavin's equation and a two-dimensional ice-structure interaction model is adopted. To verify the numerical model, dynamic analysis is performed for on of the Baltic Sea channel markers whose response patterns were presiously observed.

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Simulation of a Maglev Vehicle Running on the Flexible Guideway (유연궤도를 고려한 자기부상열차 주행 시뮬레이션)

  • Han Hyung-Suk;Kim Young-Joong;Shin Byung-Chun;Kwon Jeong-Il
    • Journal of the Korean Society for Railway
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    • v.9 no.4 s.35
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    • pp.499-503
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    • 2006
  • Maglev vehicles, which are levitated and propelled by electromagnets, often run on elevated flexible guideways comprised of steel, aluminum and concrete. Therefore, an analysis of the dynamic interaction between the Maglev vehicle and the flexible guideway is needed in the design of the critical speed, ride, controller design and weight reduction of the vehicle. This study introduces a dynamic interaction simulation technique that applies structural dynamics. Because the proposed method uses detailed 3D FE models, it is useful to analyze the deformation of the elevated flexible guideway, the dynamic stress, and the motion of the vehicle. By applying the proposed method to an urban transit Maglev vehicle, UTM01, the dynamic response is simulated and validated. From the result of the study, we concluded that the simulation of dynamic interaction between the Maglev vehicle and the flexible guideway is possible and a potential of using computational mechanics.

Simulation of the Maglev Running on the Flexible Guideway (궤도의 유연성을 고려한 자기부상열차 주행 시뮬레이션)

  • Han Hyung-Suk;Kim Dong-Sung;Lee Jong-Min
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.113-118
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    • 2005
  • Maglev vehicles, which are levitated and propelled by electromagnets, often run on elevated flexible guideways comprised of steel, aluminum and concrete. Therefore. an analysis of the dynamic interaction between the Maglev vehicle and the flexible guideway is needed in the design of the critical speed, ride, controler design and weight reduction of the vehicle. This study introduces a dynamic interaction simulation technique that applies structural dynamics. Because the proposed method uses FEM, it is useful to calculate the deformation of the elevated flexible guideway, the dynamic stress, and the motion of the vehicle. By applying the proposed method to an urban transit Maglev vehicle, UTM01, the dynamic response is simulated and validated. From the result of the study, we concluded, that the dynamic interaction between the maglev vehicle and the flexible guideway is possible.

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Dynamic Analysis of Vehicle-Bridge System by the Dynamic Condensation Method (Dynamic Condensation Method를 이용한 차량-교량계의 동적해석)

  • Han, Jae-Ik;Lee, Kyeong-Dong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.2 no.2
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    • pp.177-184
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    • 1998
  • The equation of motion on the vehicle-bridge system is established as the simultaneous equations which are combined the equation of vehicle and bridge by the interaction elements. A vehicle element is modeled as lumped masses supported by springs and dashpots, and a bridge element with pavement roughness is modeled as beam elements. An interaction element is defined to consist of a bridge element and the suspension units of the vehicle resting on the element. By the dynamic condensation method, the degrees of the freedom are eliminated, and compared with all the degrees of freedom on the bridge, the efforts of calculation is decreased. Thus, although a very small computational error is occured, the present technique appears to be computationally more efficient. It is particularly suitable for the simulation of bridges with a series of vehicles moving on the deck.

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Experimental study of dynamic interaction between group of intake towers and water

  • Wang, Haibo;Li, Deyu;Tang, Bihua
    • Earthquakes and Structures
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    • v.6 no.2
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    • pp.163-179
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    • 2014
  • Dynamic test with scaled model of a group of intake towers was performed to study the dynamic interaction between water and towers. The test model consists of intake tower or towers, massless foundation near the towers and part of water to simulate the dynamic interaction of tower-water-foundation system. Models with a single tower and 4 towers were tested to find the different influences of the water on the tower dynamic properties, seismic responses as well as dynamic water-tower interaction. It is found that the water has little influence on the resonant frequency in the direction perpendicular to flow due to the normal force transfer role of the water in the contraction joints between towers. By the same effect of the water, maximum accelerations in the same direction on 4 towers tend to close to each other as the water level increased from low to normal level. Moreover, the acceleration responses of the single tower model are larger than the group of towers model in both directions in general. Within 30m from the surface of water, hydrodynamic pressures were quite close for a single tower and group of towers model at two water levels. For points deeper than 30m, the pressures increased about 40 to 55% for the group of towers model than the single tower model at both water levels. In respect to the pressures at different towers, two mid towers experienced higher than two side towers, the deeper, the larger the difference. And the inside hydrodynamic pressures are more dependent on ground motions than the outside.

The Effects of Stabilization Exercise on Muscle Performance according to Bearing Surface (지지면에 따른 안정화 운동이 근수행력에 미치는 영향)

  • Park, Jae-Cheol;Han, Jong-Man;Kim, Yong-Seong;Kim, Yong-Nam
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.10 no.1
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    • pp.39-44
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    • 2012
  • Purpose : This study purposed to analyze how dynamic stabilization exercise on an unstable surface, and static stabilization exercise on muscle strength and endurance. Methods : For this study we sampled 9 people for the unstable surface dynamic stabilization exercise group, 9 for the stable surface static stabilization exercise group, and 9 for the control group. In order to examine muscle strength and endurance, we measured changes in the maximal voluntary isometric contraction (MVIC) using a dynamometer before, 3 weeks after, and 6 weeks after the experiment. Results : First, with regard to change in muscle strength, flexion strength showed a significant change in interaction by time (p<0.05). Extension strength showed a significant change in interaction by time (p<0.05). Second, with regard to change in endurance, flexion endurance showed a significant change in interaction by time (p<0.05). Extension endurance showed a significant change in interaction by time (p<0.05). Conclusion : In conclusion, this study confirmed significant changes in interaction between the groups and by time with regard to changes in muscle strength and endurance. These results suggest the potential of surface dynamic stabilization exercise as a clinical intervention.

Dynamic impedance of a floating pile embedded in poro-visco-elastic soils subjected to vertical harmonic loads

  • Cui, Chunyi;Zhang, Shiping;Chapman, David;Meng, Kun
    • Geomechanics and Engineering
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    • v.15 no.2
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    • pp.793-803
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    • 2018
  • Based on the theory of porous media, an interaction system of a floating pile and a saturated soil in cylindrical coordinates subjected to vertical harmonic load is presented in this paper. The surrounding soil is separated into two distinct layers. The upper soil layer above the level of pile base is described as a saturated viscoelastic medium and the lower soil layer is idealized as equivalent spring-dashpot elements with complex stiffness. Considering the cylindrically symmetry and the pile-soil compatibility condition of the interaction system, a frequency-domain analytical solution for dynamic impedance of the floating pile embedded in saturated viscoelastic soil is also derived, and reduced to verify it with existing solutions. An extensive parametric analysis has been conducted to reveal the effects of the impedance of the lower soil base, the interaction coefficient and the damping coefficient of the saturated viscoelastic soil layer on the vertical vibration of the pile-soil interaction system. It is shown that the vertical dynamic impedance of the floating pile significantly depends on the real stiffness of the impedance of the lower soil base, but is less sensitive to its dynamic damping variation; the behavior of the pile in poro-visco-elastic soils is totally different with that in single-phase elastic soils due to the existence of pore liquid; the effect of the interaction coefficient of solid and liquid on the pile-soil system is limited.

Stochastic analysis of seismic structural response with soil-structure interaction

  • Sarkani, S.;Lutes, L.D.;Jin, S.;Chan, C.
    • Structural Engineering and Mechanics
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    • v.8 no.1
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    • pp.53-72
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    • 1999
  • The most important features of linear soil-foundation-structure interaction are reviewed, using stochastic modeling and considering kinematic interaction, inertial interaction, and structural distortion as three separate stages of the dynamic response to the free-field motion. The way in which each of the three dynamic stages modifies the spectral density of the motion is studied, with the emphasis being on interpretation of these results, rather than on the development of new analysis techniques. Structural distortion and inertial interaction analysis are shown to be precisely modeled as linear filtering operations. Kinematic interaction, though, is more complicated, even though it has a filter-like effect on the frequency content of the motion.

Interactive Dynamic Simulation Schemes for Articulated Bodies through Haptic Interface

  • Son, Wook-Ho;Kim, Kyung-Hwan;Jang, Byung-Tae;Choi, Byung-Tae
    • ETRI Journal
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    • v.25 no.1
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    • pp.25-33
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    • 2003
  • This paper describes interactive dynamic simulation schemes for articulated bodies in virtual environments, where user interaction is allowed through a haptic interface. We incorporated these schemes into our dynamic simulator I-GMS, which was developed in an object-oriented framework for simulating motions of free bodies and complex linkages, such as those needed for robotic systems or human body simulation. User interaction is achieved by performing push and pull operations with the PHANToM haptic device, which runs as an integrated part of I-GMS. We use both forward and inverse dynamics of articulated bodies for the haptic interaction by the push and pull operations, respectively. We demonstrate the user-interaction capability of I-GMS through on-line editing of trajectories for 6-dof (degrees of freedom) articulated bodies.

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Improvement of Retrieval Feedback Using Dynamic Interaction Function (동적 상호작용 함수를 애용한 검색 피드백의 개선)

  • Han, Jung-Soo
    • The Journal of the Korea Contents Association
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    • v.6 no.2
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    • pp.93-98
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    • 2006
  • The paper describes a method o( user feedback in order to enhance the retrieval system effectiveness. The existing fuzzification function adapting fuzzy technique has difficulty that 4 type graph is made each time user select components. In this paper, to overcome this weak point of feedback, we proposed the interaction function using gaussian function that gives different learning rate according to choice of components with same function. We suggest the most efficient dynamic interaction function based on comparison of retrieval performance according to parameter of function. And then, we will construct the efficient retrieval system.

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