• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1044-1048
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• 2006

Nuclear power generation is very dangerous in occasion that skirt of structure by earthquake although it is high effective generation that can make a lot of energies with few raw material. when design, it must consider a lot of problems caused by an earthquake. The seismic analysis of the structure has been great concern in the engineering society with an effort to reduce the severe damages from an earthquake. So the earthquake resistant design is one of the crucial design procedures of a gate valve used in nuclear power generation. The gate valve which has the contact area between stem and bellows. Because of the contact area. The gate valve should be given high stress and frictional wear. In this thesis, Considering the gate valve which has some contact distance between stem and bellows. The gate valve which has some contact distance is analyzed by a commercial FEM code of Ansys and Then compared to the gate valve behavior which doesn't have contact distance.

• Smart Structures and Systems
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• v.10 no.6
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• pp.557-572
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• 2012

This paper focuses on the vibration control of long-span reticulated steel structures under multi-dimensional earthquake excitation. The control system and strategy are constructed based on Magneto-Rheological (MR) dampers. The LQR and Hrovat controlling algorithm is adopted to determine optimal MR damping force, while the modified Bingham model (MBM) and inverse neural network (INN) is proposed to solve the real-time controlling current. Three typical long-span reticulated structural systems are detailedly analyzed, including the double-layer cylindrical reticulated shell, single-layer spherical reticulated shell, and cable suspended arch-truss structure. Results show that the proposed control strategy can reduce the displacement and acceleration effectively for three typical structural systems. The displacement control effect under the earthquake excitation with different PGA is similar, while for the cable suspended arch-truss, the acceleration control effect increase distinctly with the earthquake excitation intensity. Moreover, for the cable suspended arch-truss, the strand stress variation can also be effectively reduced by the MR dampers, which is very important for this kind of structure to ensure that the cable would not be destroyed or relaxed.

• Smart Structures and Systems
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• v.33 no.6
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• pp.431-447
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• 2024

The Hybrid Mass Damper (HMD) has proven effective in mitigating vibrations in high-rise structures subject to seismic and wind-induced excitations. One derivative configuration of the HMD mounts an Active Mass Damper (AMD) atop a Tuned Mass Damper (TMD). However, the control efficacy of such HMDs may be compromised when confronted with loads that exceed their design parameters. Additionally, the confined structural space within high-rise structures often limits the feasibility and economic viability of retrofitting HMD systems. This study introduces an Acceleration-based Fuzzy Power Approach Rate Sliding Mode Control (AFP-SMC) algorithm aimed at enhancing the control efficacy of HMDs while minimizing their stroke and force output requirements. Employing the Canton Tower as a research prototype, an analytical model incorporating HMDs was established, and a comparative analysis between the AFP-SMC and Linear Quadratic Gaussian (LQG) control algorithms was conducted for efficacy. The control performance of the AFP-SMC control algorithm under different control parameter variations was investigated. Furthermore, by experimentally assessing the AMD subsystem within the Canton Tower, friction and ripple force formulas were derived to bolster the analytical model, thereby validating the robustness of the AFP-SMC algorithm. The results show that the proposed AFP-SMC algorithm effectively reduces the vibration response of the structure and the stroke and control force output of HMDs, and exhibits superior overall control performance and robustness compared to the LQG algorithm.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.435-442
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• 2000

In this thesis the dynamic behavior of the vehicles is analyzed while the track is subjected to lateral vibration due to earthquakes. A computer program is developed which can simulate dynamic responses of vehicles subjected to earthquake loading. The analysis considers two types of two types of vehicles : I. e. a 2-axle vehicle with 13 DOF's an da power car of K-TGV with 38 DOF's It can also consider the interaction with substructures such as tracks and bridges. El Centro record is considered as earthquake loading. The creep force module developed in this study is verified and the results of this study are compared with those of others. Furthermore he running safety of high-speed railway vehicles(K-TGV) subjected to earthquake loading is studied. Based on the results of this study the running safety of the K-TGV can be confirmed against el centro earthquake.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.560-568
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• 2005

In this paper a study on the characteristics and the reduction method for the ground vibration due to traveling tilting car are carried out. The transmitted load which induces the ground vibration is computed through a study on the interaction between tilting car and the line. Then, this load is applied into the numerical model, which is designed considering the diverse ground conditions. Through the numerical analysis according to the conditons, the characteristics and the reduction method for the ground vibration by tilting car are studied.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.360-367
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• 2003

This paper presents passive vibration control method to suppress train-induced vibration on a long-span steel arch bridge. According to the train load frequency analysis, undesirable resonance of a bridge will occur when the impact frequency of the train axles are close to the modal frequencies of the bridge. Because the first mode shape of the long-span steel arch bridge may take anti-symmetric shape along the bridge direction, however, the optimal control configuration for resonance suppression should be considered carefully In this study, bridge-vehicle element is used to estimate the bridge-train interaction precisely. From the numerical simulation of a loom steel arch bridge under TGV-K train loading, dynamic magnification influences are evaluated according to vehicle moving speed and efficient control system with passive dampers are presented in order to diminish the vertical displacement and vertical acceleration.

• Journal of Korean Association for Spatial Structures
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• v.6 no.2 s.20
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• pp.115-121
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• 2006

In recent years vibration control damper made of low yield point steel is expected to play an important role in controlling structural vibration induced earthquake and wind. But their dynamic characteristics and energy dissipation effects on the whole structure model are not clarified. In this paper, firstly, we presents the results of cyclic tests on low yield steel dampers. Secondly, forced vibration tests on existence three stories steel structure model with low yield point steel dampers are presented. Lastly, it is estimated energy amount which is dissipated through the hysteresis dampers by using two types of analytical models, hysteresis model and equivalent linear model.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.5
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• pp.57-63
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• 2008

This paper presents a seismic response prediction method using vibration tests of cabinet-type electrical equipment installed in a nuclear power plant. The proposed method consists of three steps: 1) identification of earthquake-equivalent forces based on lumped-mass system idealization, 2) identification of a state-space-equation model relating input-output measurements obtained from the vibration tests, 3) seismic prediction using the identified earthquake-equivalent forces and the identified state-space-equation. The proposed method is advantageous compared to other methods based on FEM (finite element method) model update, since the proposed method is not influenced by FEM modeling errors. Through a series of numerical verifications on a frame model and 3-dimensional shell model, it was found that the proposed method could be used to accurately predict the seismic responses, even under considerable measurement noise conditions. Experimental validation is needed for further study.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.4
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• pp.75-81
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• 2001

Fuzzy supervisory control method is studied for the active control of earthquake excited structures. The proposed algorithm supervises and tunes previously designed control gains by evaluating the state of a structure through the fuzzy inference mechanism, which uses the information of relative displacements and velocities. Example designs and numerical simulations of earthquake exited three degrees of freedom structures are performed to prove the validity of the proposed control algorithm. Comparative results with conventional LQR method show that the proposed method is effective for the vibration suppression of earthquake excited structures.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.500-511
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• 2017

Recently, as earthquakes have occurred in Gyeongju, interest in the stability of structures against vibration from earthquakes has increased. In Korea, the capacity of load resistance is mainly considered in the design of anchors. However, the vibration resistance characteristics of anchors have not been fully elucidated. The traditional type of anchor, which is a frictional resistance anchor, is often reported to fail due to vibration in construction procedures, such as blasting. The expansion type of anchor, on the other hand, could have more resistance to vibration but its capability of demonstrating vibratory resistance has to be investigated. In order to verify the vibratory resistance characteristics of expansion anchors against blasting and earthquake vibration, field tests and numerical analyses for seismic wave were performed. Field blasting test results show that the expansion anchor has better capability against vibratory load than does the frictional type anchor. Numerical analysis to earthquake also show that the expansion type anchor provides more resistance than does the frictional type anchor.