• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.642-647
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• 2001

Dynamic response of ground due to train loads is analyzed. A numerical procedure based on finite element method is used to solve two-dimensional ground response. Dynamic train loads assumed in analysis is the point acceleration on train rail with magnitude of 2330 gal and thickness of surface of soil layer assumed is 60cm. In order to consider the effect of acceleration point, dynamic responses such as response acceleration and displacement are computed as a function of distance from acceleration point on rail. In addition, simple methods which reduce dynamic effects on ground are also proposed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.271-276
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• 2001

Most engineers, related to soil and civil dynamic field, have been interested in the dynamic response of building transmitted from soil and rock to structure due to blasting. However it is not easy to estimate the dynamic response of structures and utilities due to blasting by using analytical method because of difficulties of soil modeling, prediction of excitation force and so on. In this paper, dynamic response analysis have been performed to predict vibration levels of structure due to blasting and the semi-empirical method. which is based on vibration measurement data. has been employed to consider blast vibration characteristics.

• Structural Engineering and Mechanics
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• v.54 no.1
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• pp.55-67
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• 2015

Taking the mid-span/center-point of the structure as the reference point of capturing the maximum dynamic response is very customary in the available literature of the moving load problems. In this article, the absolute maximum dynamic response of an Euler-Bernoulli beam subjected to a moving mass is widely investigated for various boundary conditions of the base beam. The response of the beam is obtained by utilizing a robust numerical method so-called OPSEM (Orthonormal Polynomial Series Expansion Method). It is underlined that the absolute maximum dynamic response of the beam does not necessarily take place at the mid-span of the beam and thus the conventional analysis needs modifications. Therefore, a comprehensive parametric survey of the base beam absolute maximum dynamic response is represented in which the contribution of the velocity and weight of the moving inertial objects are scrutinized and compared to the conventional version (maximum at mid-span).

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.160-166
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• 2011

It is difficult to clarify the dynamic response characteristics of trackbed because of various environmental conditions. However, track irregularity be affected by ununiformed bearing capacity and its dynamic response, study for dynamic response characteristics is required to investigate the cause of track irregularity and countermeasure. In this paper, the response variation for dominant frequency and vibration energy by trackbed structure and material stiffness are investigated. The analysis section is two layered ground structure that is comprised of trackbed and soft rock. This structure amplifies the energy of dominant range easily. It is evaluated to affect track irregularity on comparing by theoritical, analytical and empirical method for dynamic response of the trackbed.

• Earthquakes and Structures
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• v.13 no.3
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• pp.241-253
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• 2017

In this paper, dynamic response of the horizontal nanofiber reinforced polymer (NFRP) strengthened concrete beam subjected to seismic ground excitation is investigated. The concrete beam is modeled using hyperbolic shear deformation beam theory (HSDBT) and the mathematical formulation is applied to determine the governing equations of the structure. Distribution type and agglomeration effects of carbon nanofibers are considered by Mori-Tanaka model. Using the nonlinear strain-displacement relations, stress-strain relations and Hamilton's principle (virtual work method), the governing equations are derived. To obtain the dynamic response of the structure, harmonic differential quadrature method (HDQM) along with Newmark method is applied. The aim of this study is to investigate the effect of NFRP layer, geometrical parameters of beam, volume fraction and agglomeration of nanofibers and boundary conditions on the dynamic response of the structure. The results indicated that applied NFRP layer decreases the maximum dynamic displacement of the structure up to 91 percent. In addition, using nanofibers as reinforcement leads a 35 percent reduction in the maximum dynamic displacement of the structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.83-90
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• 2001

The site effects of local geological conditions on seismic ground motion are performed using 2D numerical method. For the analysis, a numerical method far ground response analysis using FE-BE coupling method is developed. The total system is divided into two parts so called far field and near field. The far field is modeled by boundary element formulation using the multi-layered dynamic fundamental solution that satisfied radiational condition of wave. And this is coupled with near field modeled by finite elements. In order to verify the seismic response analysis, the results are compared with those of commercial code. As a result, it is shown that the developed method can be an efficient numerical method to solve the seismic response analysis of the site effect in 2D problem.

• Journal of Korean Association for Spatial Structures
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• v.19 no.1
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• pp.53-64
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• 2019

The objective of this study is to investigate the earthquake response for the design of 100m spanned single-layer lattice dome. The plastic hinge analysis and eigenvalue buckling analysis are performed to estimate the ultimate load of single-layered lattice domes under vertical loads. In order to ensure the stability of lattice domes, it is investigated for the plastic hinge progressive status by the pushover increment analysis considering the elasto-plastic connection. One of the most effective methods to reduce the earthquake response of large span domes is to install the LRB isolation system of a dome. The authors discuss the reducing effect for the earthquake dynamic response of 100m spanned single-layered lattice domes. The LRB seismic isolation system can greatly reduce the dynamic response of lattice domes for the horizontal and vertical earthquake ground motion.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.5
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• pp.451-456
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• 2011

To ensure structural integrity of membrane type LNG tank, the rational assessment of the sloshing impact responses of tank structures should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the resulting structural responses show very complex behaviors accompanied with fluid structure interaction. So it is not easy to estimate them accurately and immense time consuming calculation process would be necessary. In this research, a simplified method to analyse the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was studied. The proposed technique based on the concept of linear combination of the triangular response functions which are the transient responses of structures under the unit triangular impact pressure acting on structures. The validity of suggested method was verified through the example calculations and applied to the dynamic structural response analysis of a real Mark III membrane type insulation system using the sloshing impact pressure time histories obtained by model test.

• 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.

• Journal of Korean Association for Spatial Structures
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• v.16 no.3
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• pp.59-66
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• 2016

This study analyze the dynamic response property of latticed domes according to natural frequency ratio of substructure. Through eigenvalue analysis, it is was confirmed that the half-open angle $30^{\circ}$ and $45^{\circ}$ dominate vibration mode of the vertical direction and the half-open angle $60^{\circ}$ and $90^{\circ}$ dominate vibration mode of the horizontal direction. Through the dynamic response analysis, it is was confirmed that the first frequency about total structure largely appears about the vertical and the horizontal direction regardless of half-open angle.