• Structural Engineering and Mechanics
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• v.70 no.3
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• pp.311-324
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• 2019

Long-span steel suspension bridges develop significant vibrations under the effect of external time-variable loadings because their slenderness. This causes significant stresses variations that could induce fatigue problems in critical components of the bridge. The research outcome presented in this paper includes a fatigue analysis of a long suspension bridge with 3300 meters central suspended span under wind action and train transit. Special focus is made on the counterintuitive interaction effects between train and wind loads in terms of fatigue damage accumulation in the hanger ropes. In fact the coupling of the two actions is shown to have positive effects for some hangers in terms of damage accumulation. Fatigue damage is evaluated using a linear accumulation model (Palmgren-Miner rule), analyses are carried out in time domain by a three-dimensional non-linear finite element model of the bridge. Rational explanation regarding the above-mentioned counterintuitive behavior is given on the basis of the stress time histories obtained for pertinent hangers under the effects of wind and train as acting separately or simultaneously. The interaction between wind and train traffic loads can be critical for a some hanger ropes therefore interaction phenomena within loads should be considered in the design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1083-1084
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1023-1024
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• 2011

• Wind and Structures
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• v.34 no.4
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• pp.335-353
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• 2022

The current work numerically investigates the transient force and dynamic response of an overhead transmission tower-line structure caused by the passage of a high-speed train (HST). Taking the CRH2C HST and an overhead transmission tower-line structure as the research objects, both an HST-transmission line fluid numerical model and a transmission tower-line structure finite element model are established and validated through comparison with experimental and theoretical data. The transient force and typical dynamic response of the overhead transmission tower-line structure due to HST-induced wind are analyzed. The results show that when the train passes through the overhead transmission tower-line structure, the extreme force on the transmission line is related to the train speed with a significant quadratic function relationship. Once the relative distance from the track is more than 15 m, the train-induced force is small enough to be ignored. The extreme value of the mid-span dynamic response of the transmission line is related to the train speed and span length with a significant linear functional relationship.

• Wind and Structures
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• v.38 no.6
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• pp.411-425
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• 2024

To investigate the optimal aerodynamic parameters of wind barriers for the T-beam of high-speed railway (HSR) bridge and the wind field of the wind barrier-train-bridge system, the three-component forces of the system and the wind pressure on the vehicle surface were tested and analyzed through the sectional model wind test. The effects of wind velocity, with/without wind barrier, the height of wind barrier, and the air permeability of the wind barrier on the aerodynamic characteristics of the train-bridge system are discussed. Additionally, a CFD numerical model is constructed to evaluate the wind environment of the bridge surface with/without the wind barrier, and the impact of wind barrier on the running safety of vehicles are analyzed. Comprehensively considering the running safety of the train and the wind-resistant stability of the bridge, it is more appropriate to set the wind barrier height H as 3.5 m and the porosity 𝛽 as 30% respectively.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.496-500
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• 2010

Understanding train-wind is the best method to know how to optimize subway ventilation system. The capacity and efficiency of the subway ventilation system are known by pressure and velocity while train runs. Analysis of the internal flow in subway tunnel and around subway station are studied using numerical methods. Characteristics of internal flow and influence of subway ventilation system for the subway station with platform screen door and tunnel are analyzed by unsteady state analysis. Velocity and pressure of train wind transformation are compared at around subway ventilation system and the internal flow is investigated at the subway tunnel.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.7
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• pp.652-657
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• 2004

Development of underground space in urban area has a huge amount of potential to ease the limitations on the land use and the efficiency especially in urban area. Considering public transportation in urban area, subway system could be one of the most efficient and practical approaches. Subsequently this leads the public to have more chances to experience the indoor air quality (IAQ) in subway systems. In this study, it was aimed to produce useful data for the IAQ control in subway environments, Specifically the train-induced wind has been investigated by means of field survey and analysis. The recent updates including the quantified characteristics of train-induced wind are presented in this paper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.5
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• pp.443-449
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• 2014

This study aims to develop a Flywheel Energy Storage System (FESS) that uses wind power produced when an urban train is in motion, by utilizing a mounted turbine. This system was designed to generate and store electric power from wind power of a travelling urban train. The flywheel was designed to continue rotation using a one-way clutch bearing installed in the turbine shaft pulley, even in cases where the urban train decelerates or stops. This FESS can generate an additional 44% of electric power in comparison to a system not equipped with a flywheel. The generated power and operational features of the FESS were evaluated and verified through a wind tunnel test. The results show that the electric power stored in the FESS could supply auxiliary power for urban train components or service equipment, such as charging mobiles, Wi-Fi modules, and electric lights.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.36-40
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• 2012

Pitch control of wind turbine is activated above rated wind speed for the purpose of rated power regulation. When we design pitch controller, its gain-scheduling is essential due to nonlinear characteristics of aerodynamic torque. In this study, 2-mass model including a vibration mode of drive-train for a 2 MW wind turbine is considered and pitch control with gain-scheduling using a linearization analysis of the nonlinear aerodynamic torque is applied. Some simulation results for the pitch gain-scheduling under step wind speed are presented and investigated. It is shown that gain-scheduling in pitch control is important especially in the region of high wind speeds when there exists a vibration mode of drive-train.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1614-1622
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• 2004

When a High Speed Train (HST) passes through a station with no stop, effects of wind pressure transients caused by this passing train have to be considered for the safety of passengers on the platform and for the possible structural safety problems as well. In Gwangmyeong and Daejeon stations of the Korean high speed railroad, tunnels inside stations for the passing train are proposed to reduce the noise and wind pressure transients to the passengers on the platform. In the present study, transient 3-D full Navier-Stokes solutions with moving mesh to implement train movement are obtained and compared with the results obtained by the towing tank experiment. Investigations on flow phenomena for various train speeds and design modifications are also performed.