• 한국전산구조공학회논문집
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• 제32권1호
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• pp.7-16
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• 2019

본 논문에서는 해양플랜트용 매니폴드 구조물의 내진해석을 위해, 단순화 모델에 대해 응답스펙트럽해석(RSA) 및 시간이력해석(THA)을 여러 조건으로 진행하여 비교 검토하였다. 응답스펙트럼해석은 ISO19901-2에 따른 내진설계 절차를 이용하였다. 시간이력해석의 경우, 응답스펙트럼으로 가속도와 변위에 대한 지진이력을 인공적으로 만든뒤 Explicit와 Implicit 솔버를 사용하여 해석하였다. 단자유도 모델을 사용하여 해석방법을 검증하였으며, 매니폴드 구조물을 단순화한 모델에서 시간이력해석과 응답스펙트럼해석법의 차이를 분석하였다. 복잡한 실제 구조물에 대해서 직접적인 시간이력해석은 불가능하므로 응답스펙트럼해석법을 적용하였고, 단순화 모델에서 분석한 결과 차이를 활용하여 실제 구조물의 안전성을 판단하였다.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2716-2727
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• 2021

The core shroud is one of the most important internal components of the reactor vessel internals because it meets the neutron fluence directly emitted by the nuclear fuel. In particular, dynamic effects for an earthquake should be evaluated with respect to the neutron irradiation flux. As a prerequisite to this study, simplified and detailed finite element models are developed for the core shroud using the ANSYS Design Parametric Language. Using the El Centro earthquake, seismic analyses are performed for the simplified and detailed core shroud models. Modal characteristics are obtained and their results are used for a time history analysis. Response spectrum analyses are also performed to access the degree of seismic excitation. The results of these analyses are compared to investigate the response characteristics between the simplified and detailed core shroud models from the time history and response spectrum analyses.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.797-816
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• 2014

Cooling tower is analyzed as an assembly of layered nonlinear shell elements. Geometric representation of the shell is enabled through layered nonlinear shell elements to define the different layers of reinforcements and concrete by considering the material nonlinearity of each layer for the cooling tower shell. Modal analysis using Ritz vector analysis and nonlinear time history analysis by direct integration method have been carried out to study the effects of the inclination of the supporting columns of the cooling tower shell on its dynamic characteristics. The cooling tower is supported by I-type columns and ${\Lambda}$-type columns supports having the different inclination angles. Relevant comparisons of the dynamic response of the structural system at the base level (at the junction of the column and shell), throat level and at the top of the tower have been made. Dynamic response of the cooling tower is found to be significantly sensitive to the change of the inclination of the supporting columns. It is also found that the stiffness of the structure system increases with increase in inclination angle of the supporting columns, resulting in decrease of the period of the structural system. The participation of the stiffness of the tower in structural response of the cooling tower is fund to be dependent of the change in the inclination angle and even in the types of the supporting columns.

• 한국공간구조학회논문집
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• 제14권1호
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• pp.77-84
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• 2014

Simple 3, 10, and 30-story buildings with a nonstructural element which is located at roof or near the middle of the building height are selected. Based on 2009 Korean Building Code, the seismic design force applied at the nonstructural element is evaluated. Response spectrum analysis is conducted with the design response acceleration spectrum of 2009 Korean Building Code and the analytical response is compared with the seismic design force from the Code. Furthermore, an artificial earthquake based on Korean design response acceleration spectrum and the 50% intensity of El Centro earthquake, which can be considered as the maximum future earthquake possibly occurring in Korea, are selected to conduct time history analysis. When the period of the nonstructural element is shorter than 0.06 second or longer than that of the 1st period of each building, the Code equations of seismic design force for nonstructural element seems to be appropriate. However, the period of the nonstructural element is close to the one of the building's higher mode periods including the 1st period, seismic force of the nonstructural element might exceed the Code specified seismic design force.

• 한국공간구조학회논문집
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• 제18권3호
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• pp.105-116
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• 2018

The objective of this study is to investigate the response reducing effect of a seismic isolation system installed between 300m dome and supports under both horizontal and vertical seismic ground motion. The time history analysis is performed to investigate the dynamic behavior of single layer lattice domes with and without a lead rubber bearing seismic isolation system. In order to ensure the seismic performance of lattice domes against strong earthquakes, it is important to investigate the mechanical characteristics of dynamic response. Horizontal and vertical seismic ground motions cause a large asymmetric vertical response of large span domes. One of the most effective methods to reduce the dynamic response is to install a seismic isolation system for observing seismic ground motion at the base of the dome. This paper discusses the dynamic response characteristics of 300m single layer lattice domes supported on a lead rubber seismic isolation device under horizontal and vertical seismic ground motions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.732-737
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• 2005

This paper performed pseudo static analysis and dynamic analysis for CFRD and evaluated reliability with the results of Shaking Table Test. The Seismic coefficient method, modified seismic coefficient method, Newmark method of Pseudo static analysis and frequency domain response analysis, time domain history analysis of dynamic analysis were used. The analysis results were differ between analysis method, but the trends of acceleration and displacement were good agreement with the results of shaking table test.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.21-32
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• 2002

일반적으로 응답스펙트럼 해석법은 건물의 지진해석에 널리 사용되고 있지만 기계하중이나 이동하중 등에 의하여 발생하는 진동에 대한 해석에는 시간이력해석이 주로 사용되고 있다. 그런데, 시간이력해석법은 정확한 반면 매우 복잡하고 어려우며 많은 시간을 필요로 한다. 따라서, 본 논문에서는 동적하중을 받는 구조물의 최대응답을 응답스펙트럼해석법을 이용하여 간편하게 계산하는 방법을 제시하고자 한다. 우선, 이 해석법의 해석과정에 대하여 알아보았으며, 복수절점에 동적 하중을 받는 경우에 대해서 해석시간 및 메모리를 줄이는 방법을 제시하였다. 다음으로는 이동하중을 받는 경우에 대하여 구조물의 최대응답을 구하는 방법에 대하여 알아보았다. 마지막으로 예제를 통하여 시간이력해석을 수행하여 얻은 최대응답과 응답스펙트럼해석에 의한 최대응답을 비교하여 제시한 해석법의 정확성을 확인하였다.

• 한국전산구조공학회논문집
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• 제20권5호
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• pp.623-628
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• 2007

마찰형 감쇠를 갖는 구조물은 구조물의 고유주기, 하중의 특성, 그리고 외부하중에 대한 마찰력의 상대적인 크기에 따라 강한 비선형성을 나타내므로, 구조물의 최대응답을 예측하기 매우 어렵다. 기존의 연구에서는 비선형 시스템을 등가의 선형 시스템으로 치환하거나, 구조물의 비선형 시간이력해석을 통한 응답스펙트럼 분석에 의한 간단한 확률해석에 의해 수행되었다. 지진 하중은 불확실성과 불규칙성을 갖고 있기 때문에 확률적으로 정의된다면, 지진하중을 받는 마찰형 감쇠를 갖는 구조물의 응답 역시 확률분포를 나타낼 것이다. 본 논문에서는 Kanai-Tajimi 필터를 이용해 생성된 인공지진하중에 대해 마찰형 감쇠를 갖는 구조물의 비선형 시간이력 해석이 수행되었다. 그리고 정규분포 확률밀도 함수에 선형 회귀분석을 통해 얻어진 구조물의 주기와 마찰력의 크기에 의한 변수를 업데이트 시킨 마찰형 감쇠를 갖는 구조물의 변위 응답 확률밀도함수식이 제시된다.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1577-1586
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• 2023

Safety qualification of a steam generator is a crucial issue related to faulted condition design loads, including earthquake loads, and it should be ensured that the structural integrity of a steam generator does not exceed its design load. Using data from the Gyeongju and Pohang earthquakes, the two most powerful recorded seismic events in Korea, seismic analyses of a typical steam generator are conducted in this study. The modal characteristics are used to develop an input deck for these analyses. With a time history analysis, the responses of the steam generator in the event of an earthquake are obtained. In particular, the displacement, velocity, and acceleration responses are obtained in the time domain, with these outcomes then used for a detailed structural analysis as part of the ensuing assessment. The response spectra are also generated to determine the response characteristics in the frequency domain, focusing on the response comparisons between the Gyeongju and Pohang earthquakes. Structural integrity can be ensured by performing additional analysis using results obtained from the time history analysis considering the input excitations of various earthquakes considered in the design.

• 복합신소재구조학회 논문집
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• 제2권4호
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• pp.28-34
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• 2011

본 연구는 인공지진파 및 기록 지진파를 이용하여, KBC2009 규준으로 설계된 강구조 건물의 거대 건물에 대한 내력 여유도를 평가하는 것을 목표로 하고 있다. 이 논문에서는 검정에 있어서 콘크리트 슬래브로 층강성이 고정되어 있는 2-D 프레임을 고려하였고, 각각의 프레임을 구성하고 있는 보와 기둥 부재는 각 부재단에 소성힌지를 적용하였다. 검정에 사용한 해석법은 응답 스펙트럼을 이용한 모드 해석과 기록 및 인공지진파를 이용한 시간이력해석을 선택하여 모델의 거동을 조사하였으며 해석에서는 P-delta 효과를 고려한다.