• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.3
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• pp.241-248
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• 2015

There are a lot of equipment related to safety and electric power production in nuclear power plants. The structure and equipment in NPPs were generally designed considering a high safety factor to remain in the elastic zone under earthquake load. However it is needed to revaluate the seismic capacity of the structure and equipment as the magnitude of earthquake was recently increased. In this study the floor response due to the nonlinear behaviors of structure was analyzed and the inelastic structural response factor was calculated by the nonlinear time history analysis. The inelastic structural response factor was calculated by the EPRI method and the nonlinear analysis method to realistically evaluate the seismic fragility for the equipment. According to the analysis result, it was represented that the inelastic structural response factor was affected by the natural frequency of equipment, the location of equipment and the dynamic property of structure.

• Computational Structural Engineering
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• v.10 no.3
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• pp.52-57
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• 1997

본 고에서는 부유구조물의 특징과 설계시 고려사항, 작용하는 하중, 구조응답 추정방법 등을 살펴보았다. 현재 국내에는 해상에 설치된 부유구조물은 아직 없으나 조선소에서 해상 발전 플랜트나 담수화설비 등을 수출한 실적은 있다. 그러나 설계기술의 많은 부분을 외국에 의존하고 있어 부유구조물의 설계 및 동적 구조응답해석 분야에 대한 국내의 많은 연구가 요구된다 하겠다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.10a
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• pp.160-164
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• 1994

본 논문에서는 구조물의 진동으로 야기되는 소음원을 규명하기 위해 구조물 동작중의 응답신호를 측정한다. 먼저 응답 신호벡터에서 스펙트럼행렬을 구성하여 특이치 분리법을 수행한다. 특이치의 정보로 구조물의 응답에 영향을 미치는, 서로 독립적으로 작용하는 주 가진원을 파악한다. 간단한 구조물에 대해, 본 논문에서 적용된 기법의 유용성 및 물리적 성질을 검토한 후, 자동차 파워트레인이 구조 진동이 실내 소음에 미치는 구조적 소음을 실험을 통해 규명한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.5
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• pp.309-317
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• 2021

In this paper, we present the evaluation results for the conservatism of the response acceleration method (RAM), for seismic response analysis of box-type power cable tunnels. We studied 50 examples, considering the cross sections of 25 power cable tunnels, and two soil conditions for each power cable tunnel. A refined dynamic analysis method considering the soil-structure interaction was further employed to evaluate the conservatism of the RAM. The comparison revelated that the seismic responses computed using the RAM were consistent with those obtained using the refined method, since the averages of response ratio (defined as the ratio of the response by RAM to that of the refined method) approached 1.0, and the standard deviations of the response ratio were less than 5%. Finally, we found that applying a load factor of 1.1 to the response of the RAM allowed for a conservative design for seismic loads.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.1
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• pp.154-162
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• 2019

Large scale damage has been globally increased due to natural disasters such as earthquake. Although a variety of studies secured seismic performance of buildings, casualties and economic loss have occurred because of poor security of seismic performance in non-structural components. Structure's location on which non-structural components are installed and characteristics of vibration occurring on each position of structures are varied, so a response spectrum is required for each position of structures. In addition, a response spectrum occurring in a structure is different, depending on the form of it and positions on which it is installed. Therefore, selection of a response spectrum is important, so a definite method for calculating the response spectrum which acts on non-structural components is necessary. A method for choosing a response spectrum is suggested in this paper, and a structural analysis was conducted with the suggested method, by selecting a ground response spectrum and a structural system, which may occur in Korea. Moreover, it helps create a response spectrum necessary for a seismic test of non-structural components, by suggesting the method for deduction it, with a simple formula.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.4
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• pp.649-659
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• 1999

본 연구에서는 점탄성감쇠기가 설치된 비비례 감쇠 구조물의 바람에 대한 확률적 응답을 진동수영역에서 구하였다. 복소수 고유치 및 고유백터를 바탕으로 모드중첩법을 이용하여 응답의 RMS 값을 구하고 그것을 근사적인 방법인 모드 변형에너지법에서 얻은 결과와 비교하였다. 또한, 가력 진동수에 따라서 변하는 점탄성감쇠기의 강성 및 감쇠 계수를 상수로 모형화하였을 때의 풍응답 해석 결과의 정확성을 진동수영역에서 검증하였다. 해석결과에 의하면 감쇠기의 진동수 의존 특성은 구조물의 1차 고유 진동수에 의해서 비교적 정확하게 표현되었고, 모드 변형에너지법은 대체로 정확한 결과를 도출하였지만, 가속도 응답을 구할 때에는 다소 큰 오차를 유발하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.6 s.46
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• pp.13-19
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• 2005

Floor response spectra for dynamic response of subsystem such as equipment, or piping in nuclear power plants are usually generated without considering dynamic interaction between main structure and subsystem. This study describes the analytic method in which equipment response spectra can be obtained through dynamic analysis considering equipment-structure Interaction(ESI). In this method, dynamic response of the equipment by this method is based on a dynamic substructure method in which the equipment-structure system is partitioned into the single-degree-ol-freedom system(SDOF) representing the equipment and the equipment support impedance representing the dynamic charactenstics of the structure ai the equipment support. A family of equipment response spectra is developed by applying this method to calculate the maximum responses of a family of SDOF equipment systems with wide banded equipment frequency, damping ratio, and mass. The method is validated by comparing the floor response spectrum from this method with the floor response spectrum generated from the rigorous analysis including equipments on the containment building of a prototypical nuclear power plant. in order to Investigate ESI effect in the response of equipment, response values from the method and the conventional approach without considering ESI are compared for the equipment having the mass less than 1% of the total structural mass. Response spectra from the method showed lower spectral amplitudes than those of the conventional floor response spectra around controlling frequencies.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.675-681
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• 2007

A numerical procedure is described for estimating the effects of the multi-directional irregular waves on the structural responses of the Tension Leg Platform (TLP). The numerical approach is based on a three dimensional source distribution method for hydrodynamic forces, a three dimensional frame analysis method for structural responses, in which the superstructure of TLP is assumed to be flexible instead of rigid. Hydrodynamic and hydrostatic forces on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in structural analysis. The spectral description used in spectral analysis of directional waves for the linear system of a TLP in the frequency domain is sufficient to completely define the structural responses. This is due to both the wave inputs and responses are stationary Gaussian random process of which the statistical properties in the amplitude domain are well known. The numerical results for the linear motion responses and tension variations in regular waves are compared with the experimental and numerical ones, which are obtained in Yoshida et al.(1983). The results of comparison confirmed the validity of the proposed approach.

• Bulletin of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.13-20
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• 1996

해양공간 활용을 위해 예상되는 부유식 해양구조물은 단위구조들이 결합된 형태의 초대형 구조물로서 단위 구조물간의 탄성변형 문제가 매우 중요시되고 있으며 이에 따라 단위구조물간의 상호작용이 고려된 유체력 산출과 탄성응답이 고려된 해석법의 개발이 전세게적으로 활발히 이루어지고 있다. 독립 부유구조물 자체의 크기가 대형화될 때 발생하는 탄성 변형 또한 구조 해석 및 진동관점에서 중요한 고려사항이며, 이는 조선공학분야에서 유탄성 해석기법에 바탕을 두고 연구가 활발히 진행중이다. 본 고에서는 부유구조물의 설계에 있어 핵심기술중 하나인 파랑응답 해석기술의 현황에 대해 살펴보고 현재 한국기계연구원에서 수행중인 국책연구개발사업 "해양공간이용 대형 복합플랜트 개발"의 세부과제인 "부유구조물 파랑응답 해석기법 개발"의 추진내용에 대해 환경 하중/응답해석기술, 계류시스템 설계/해석기술, 유탄성응답 해석기술로 나누어 소개하고자 한다. 해석기술로 나누어 소개하고자 한다.

• Journal of Korean Association for Spatial Structures
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• v.9 no.1
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• pp.47-52
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• 2009

In this study, it is demonstrated by a pseudo dynamic earthquake response tests that combination of semi-rigid partial-strength using the high performance-high strength bolts and inter-story hysteretic damper system creates a fairly good structural system that satisfies not only the serviceability requirement under moderate earthquakes but unexpected failure of damper system.