• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1719-1724
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• 2010

In the areas susceptible to vibration and noise induced by railway traffic such as downtown area and stations under railway lines, the vibration and the structure-borne noise can be solved by floating slab track system separating the entire track structure from its sub-structure using anti-vibration mat or springs. In other countries, the core technologies for vibration-proof design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the design technology of system and components are not yet developed, the foreign systems are being introduced without any adjustment. Thus, in this study, the vibration isolator has been developed and its performance are investigated by the dynamic analysis of a station structure under railways lines and the floating slab track system. For this purpose, the loads transferred from the vibration isolator of the floating slab track were evaluated by train running simulation considering vehicle-track interaction, and then the dynamic analysis of station structure subjected to these loads was performed. The dynamic analysis results show that the proposed floating slab track can reduce the vibration of structure by about 25dB compared with that in conventional ballast track without floating system.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.5
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• pp.285-293
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• 2016

Soil-foundation-structure interaction (SFSI) is one of the important issues in the seismic design for evaluating the exact behavior of the system. A seismic design of a structure can be more precise and economical, provided that the effect of SFSI is properly taken into account. In this study, a series of the dynamic centrifuge tests were performed to compare the seismic response of the single degree of freedom(SDOF) structure on the various types of the foundation. The shallow and pile foundations were made up of diverse mass and different conjunctive condition, respectively. The test specimen consisted of dry sand deposit, foundation, and SDOF structure in a centrifuge box. Several types of earthquake motions were sequentially applied to the test specimen from weak to strong intensity of them, which is known as a stage test. Results from the centrifuge tests showed that the seismic responses of the SDOF structure on the shallow foundation and disconnected pile foundation decreased by the foundation rocking. On the other hand, those on the connected pile foundation gradually increased with intensity of input motion. The allowable displacement of the foundation under the strong earthquake, the shallow and the disconnected pile foundation, have an advantage in dissipating the earthquake energy for the seismic design.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.859-865
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• 1991

The paper proposes a design of high-speed dynamic CMOS PLA (Programmable Logic Array) which performs stable circuit operation. The race problem which nay occur in a NOR-NOR implementation of PLA is free in the proposed dynamic CMOS PLA by delaying time between the clocks to the AND- and to the OR-planes. The delay element has the same structure as the product line of the longest delay in the AND p`ane. Therefore it is unnecessary to design the delay element or to calculate correct delay time. The correct delay generated by the delay element makes the dynamic CMOS PLA to perform correct and stable circuit operation. Theproposed dynamic CMOS PLA has few variation of switching delay with the increasing number of inputs or outputs in PLA. It is verified by SPICE circuit simulation that the proposed dynamic CMOS PLA has the better performance over existing dynamic CMOS PLA's.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.682-686
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• 2001

A fundamental structural design consideration for a vehicle is the overall vibration characteristics in bending and torsion. Vibration characteristics of a vehicle system are mainly influenced by dynamic stiffness of the vehicle body structure and material and physical properties of the components attached to the vehicle body structure. The first step in satisfying this requirement is to obtain a satisfactory dynamic model of the vehicle structure. In this paper. modeling techniques of the vehicle components are presented and the effects of the vehicle components on the vibration characteristics of the vehicle are investigated,

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.458-461
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• 2008

The primary objective of this study is to provide simple analytical tools to estimate dynamic characteristics of steel framed floor system in hospital building for vibration serviceability due to human activities, bogie, medical equipment. and so on. In order to evaluate the dynamic characteristics and vibration levels according to steel framed floor system, we had executed impact test and measurement on steel structure floor system in various hospital buildings. But perhaps most importantly, how to make the most of deduced design factor for design of hospital building. therefore we presented the access method such as the three-dimensional F.E. numerical analysis on the basis of the design drawing, and the properties of all floors for estimation of vibration level in hospital building.

• Earthquakes and Structures
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• v.10 no.3
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• pp.669-680
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• 2016

In this paper, the underground box structure is discretized as a system with limited freedoms, and the explosion seismic wave is regarded as series of dynamic force acting on the lumped masses. Based on the local deformation theory, the elastic resistances of the soil are simplified as the effects of numbers of elastic chain-poles. Matrix force method is adopted to analyze the deformation of the structure in elastic half space. The structural dynamic equations are established and by solving these equations, the axial force, the moment and the displacement of the structure are all obtained. The influences of size ratio, the incident angle and the rock type on the dynamic response of the underground box structure are all investigated through a case study by using the proposed method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.62-72
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• 1999

In this study, the griding machine bed was designed and analyzed by using epoxy-granite. Finite element technique was employed to design and analyze the composite bed structure. Von Mises stress and relative displacements between a tool and a workpiece were checked to compare a cast iron bed structure with a composite bed structure. Dynamic features of structures were also studied according to the process of modal analysis through natural frequency and mode shape measurement. Another improved model was also designed using the accumulation of knowledge based on the use of the structural analysis and experiments. Comparing with the cast iron bed structure, the composite bed structure maintains better functions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.12
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• pp.1066-1072
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• 2013

In this work, active control algorithm is adopted to reduce delamination effects of the damaged composite structure and control performance with MFC actuator is numerically evaluated. Finite element model for the damaged composite structure with piezoelectric actuator is established based on improved layerwise theory. In order to achieve high control performance, MFC actuator, which has increased actuating force, is considered as a piezoelectric actuator. Mode shapes and corresponding natural frequencies for the damaged smart composite structure are studied. After design and implementation of active controller, dynamic characteristics of the damaged smart composite structure are investigated.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.337-346
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• 2000

Earthquake is a natural disaster accompanied by damage of human and properties caused by the ground motion, crustal movements, faults as well as tidal wave. The earthquake is known to occur mostly in earthquake-prone areas and the Korean Peninsula is known to be relatively safe in terms of geological characteristics. In order to withstand on severe environmental dynamic random load such as an earthquake, the large structure need to be designed to withstand the anticipated seismic tremor. The seismetic design is essential for building structures, bridges, and large structures which is handles explosive gases. Thus, the necessity of earthquake resistant analysis for large structure is growing and the capability of dynamic analysis should be obtained. In this thesis, dynamic responses of a high building(height 60m, width 18) which subjected to random earthquake load are presented which responses are derived using dynamic analysis methods such as response spectrum analysis, mode superposition and direct integration. Each results are also compared to review the merit of each methods.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.344-348
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• 2010

The intent of this paper is to describe a neural network structure called multi dynamic neural network(MDNN), and examine how it can be used in developing a learning scheme for computing robot inverse kinematic transformations. The architecture and learning algorithm of the proposed dynamic neural network structure, the MDNN, are described. Computer simulations are demonstrate the effectiveness of the proposed learning using the MDNN.