Bigdeli Y.,Kunsan National University |
Kim D.,Kunsan National University |
Chang S.,TE Solution Co.
Structural Engineering and Mechanics | Year: 2014
This paper develops a new nonlinear model for active control of three-dimensional (3D) irregular building structures. Both geometrical and material nonlinearities with a neuro-controller training algorithm are applied to a multi-degree-of-freedom 3D system. Two dynamic assembling motions are considered simultaneously in the control model such as coupling between torsional and lateral responses of the structure and interaction between the structural system and the actuators. The proposed control system and training algorithm of the structural system are evaluated by simulating the responses of the structure under the El- Centro 1940 earthquake excitation. In the numerical example, the 3D three-story structure with linear and nonlinear stiffness is controlled by a trained neural network. The actuator dynamics, control time delay and incident angle of earthquake are also considered in the simulation. Results show that the proposed control algorithm for 3D buildings is effective in structural control. Copyright © 2014 Techno-Press, Ltd.
Chang S.,TESolution Co. |
Kim D.,Kunsan National University |
Kim D.H.,Kunsan National University |
Kang K.-W.,Kunsan National University
Journal of Earthquake Engineering | Year: 2012
An active vibration control technique for building structures using a learning-based lattice pattern controller (LBLPC) is proposed in this article. The training pattern of the LBLPC is composed of a lattice form for the control force and a state vector. The training pattern was trained by a learning rule using the gradient descent method (GDM) in earthquakes. The LBLPC calculates the control force using only the adjacent input information, thus making the corresponding calculation process much faster. A three-story building in the El Centro earthquake was used to train the LBLPC. And the California and Northridge earthquakes were used to verify the performance of the proposed method. In order to prove the control capability of the LBLPC, the control results of the LBLPC were compared with those of a lattice type probabilistic neural network (LPNN) in a numerical example. The results demonstrated that the proposed LBLPC algorithm reduces the response of the building structure during earthquakes more effectively than the LPNN. © 2012 Copyright A. S. Elnashai & N. N. Ambraseys.
Kim Y.M.,Korea Institute of Construction Technology |
Kim Y.S.,TE Solution Co. |
Hwang J.S.,Chonnam National University
Bridge Maintenance, Safety, Management and Life Extension - Proceedings of the 7th International Conference of Bridge Maintenance, Safety and Management, IABMAS 2014 | Year: 2014
The example of application of a tuned mass damper to a cable-stayed bridge during construction is illustrated; design, analysis, manufacture, installation and maintenance. A linear active mass damper system is proposed and developed to reduce vibration of long-span bridges subjected to wind loads. The linear active mass damper system was designed and built for a scaled bridge model; furthermore, the system was designed to reduce vibration in two degrees of freedom. Wind tunnel test was carried out with the damper deactivated and activated to evaluate the performance of the system. Test results showed that the linear active mass damper system was able to control wind-induced torsional rotation and vertical displacement with high efficiency. In addition, the AMD mock-up test with a scale of 1/10.5 was carried out for the vertical direction. We could find the vibration control effects through the performance test. © 2014 Taylor & Francis Group.
Cho B.-H.,Ajou University |
Jo J.-S.,POSCO |
Joo S.-J.,TESolution Co. |
Kim H.,Kyungpook National University
Computer-Aided Civil and Infrastructure Engineering | Year: 2012
For a secondary mass damper such as tuned liquid damper (TLD) or tuned liquid column damper (TLCD), whose moving mass is liquid, it is impossible to prefabricate the damper in a factory for the identification of dynamic properties. Also, it is not easy to prefabricate a concrete tuned mass damper (TMD), whose moving mass is made of concrete, in a factory. In this article, an identification method for finding dynamic properties of secondary mass dampers based on the full-scale field test is presented. Decoupled equations of motion are derived from a coupled equation of motion of building and damper. The decoupled equations of motion are then used for system identification using the response of the damper as an input and the response of the building as an output. The proposed method is applied to numerical examples and an actual TMD and TLCD installed in buildings. © 2011 Computer-Aided Civil and Infrastructure Engineering.
Eem S.-H.,KAIST |
Jang D.-D.,KAIST |
Jung H.-J.,KAIST |
Joo S.-J.,TE Solution Co.
Advanced Science Letters | Year: 2012
In this paper, the effective damping ratio for a pendulum structure, such as a ropeway carrier and a cable car, employing a pendulum-type tuned mass damper (PTMD) is first formulated. Also, the other parameters of a PTMD, such as the mass ratio, the optimal frequency ratio and the optimal damping ratio, are derived from the equations of motion. And then, a numerical example is presented to validate the effectiveness of the PTMD design procedure using the proposed effective damping ratio. The results demonstrate that the parameters including the effective damping ratio derived in the study could be effectively used for designing a PTMD for a ropeway carrier under wind loads. © 2012 American Scientific Publishers. All rights reserved.
Kwon K.-S.,Seoul National University |
Kim D.-W.,TESolution Co. |
Kim R.-W.,Seoul National University |
Ha T.,Seoul National University |
Lee I.-B.,Seoul National University
Biosystems Engineering | Year: 2016
The government of Korea has announced a plan to develop large-scale greenhouse complexes on reclaimed coastal land. Wind characteristics over coastal regions are different from those of inland because of topographical and meteorological characteristics. A greenhouse facility is classified as a light-weight structure that is vulnerable to heavy wind loads. Reference to the newly modified greenhouse design standards, particularly for the reclaimed lands, has been required to ensure structural safety in strong winds. To evaluate the structural safety of greenhouses according to the wind characteristics for coastal reclaimed lands, the wind environments of these regions were simulated in a large scale Eiffel type wind tunnel. Variations in the windward terrain roughness were computed using the wind and turbulence intensity profiles based on ESDU (Engineering Sciences Data Unit, E01008) code. The wind pressure coefficients of four typical single-span greenhouses used in Korea, (Even-span, Three-quarter, Peach and Mono-span) were measured in the wind tunnel according to wind direction, roof slope and the radius of curvature of the roof. The wind pressure coefficients of the 4 types of greenhouses were proposed in terms of their structural design and cladding. The proposed wind pressure coefficients values will be valuable for greenhouse designers and manufacturers. © 2015 IAgrE.
Kim W.,TESolution Co. |
Tamura Y.,Tokyo Polytechnic University |
Yoshida A.,Tokyo Polytechnic University
Advances in Structural Engineering | Year: 2013
This present study investigated interference effects of local peak pressure on a principal building for various locations of an interfering building for various wind directions. To obtain further information and to explain the interference mechanism for enhanced local peak pressure due to the interfering building, simultaneous pressure measurements and flow visualizations using a dynamic particle image velocimetry (DPIV) system were performed in the wind tunnel of the Shimizu Institute of Technology. Experimental results have been examined and presented of effects of an interfering building and wind direction on local peak pressures. DPIV results have shown that, for an oblique configuration, a strong shear layer generated by the interfering building directly hits the principal building, which increases the momentum over its upper surface, resulting in a high pressure coefficient near the leading edge of its upper surface.
Kim Y.-M.,Daewoo EandC Co. |
Kwak Y.-H.,Daewoo EandC Co. |
Kim D.-Y.,Daewoo EandC Co. |
Joo S.-J.,TE Solution Co. |
Kim Y.-S.,TE Solution Co.
Large Structures and Infrastructures for Environmentally Constrained and Urbanised Areas | Year: 2010
The TMD (Tuned Mass Damper) method of construction is proposed to the cable stayed bridge or the similar structure to suppress the wind-induced vibrations and ensure the aerodynamic stability. This stabilizing method of construction by TMD does not need any foundations. Thus it could solve the environmentally constrained problems by excavation or dredge of the ground and the risk of the traffic collisions. Moreover, it is more economical and workable in comparison with the temporary tied-down cables. It is shown that the vibration control by TMD is the most efficient solution to stabilize the bridge during construction regarding wind. The three-pylon cable stayed bridge at the Busan~Geoje Fixed Link in the south-eastern part of Korea is introduced to show the example for the application of the TMD method of construction to solve the environmentally constrained problems.
Lee S.-W.,TESolution Co. |
Jeong J.-H.,UA |
Knez K.P.,UA |
Min J.-H.,UA |
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016
Dynamic displacement is one of the most important measurands in wind tunnel tests of structures. Laser sensors or optical sensors are usually used in wind tunnel tests to measure displacements. However, these commercial sensors have limitations in its use, cost and installation despite of their good performance in accuracy. RINO (Real-Time Image-processing for Non-contact monitoring), an iOS software application for dynamic displacement monitoring, has been developed in the previous study. In this study, feasibility of RINO in practical use for wind tunnel tests is explored. Series of wind tunnel tests show that performances of RINO are comparable with those of conventional displacement sensors. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
Park J.,Korea Advanced Institute of Science and Technology |
Jung H.-J.,Korea Advanced Institute of Science and Technology |
Lee S.-W.,TESolution Co. |
Park J.,Inha University
Energies | Year: 2015
This paper proposes an innovative building-integrated wind turbine (BIWT) system by directly utilizing the building skin, which is an unused and unavailable area in all conventional BIWT systems. The proposed system has been developed by combining a guide vane that is able to effectively collect the incoming wind and increase its speed and a rotor with an appropriate shape for specific conditions. To this end, several important design issues for the guide vane as well as the rotor were thoroughly investigated and accordingly addressed in this paper. A series of computational fluid dynamics (CFD) analyses was performed to determine the optimal configuration of the proposed system. Finally, it is demonstrated from performance evaluation tests that the prototype with the specially designed guide vane and rotor for the proposed BIWT system accelerates the wind speed to a sufficient level and consequently increases the power coefficient significantly. Thus, it was confirmed that the proposed system is a promising environment-friendly energy production system for urban areas. © 2015 by the authors.