• Structural Engineering and Mechanics
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• 제27권5호
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• pp.541-554
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• 2007

A simplified yet effective design procedure for viscous dampers was presented based on improved capacity spectrum method in the context of performance-based seismic design. The amount of added viscous damping required to meet a given performance objective was evaluated from the difference between the total demand for effective damping and inherent damping plus equivalent damping resulting from hysteretic deformation of system. Application of the method is illustrated by means of two examples, using Chinese design response spectrum and mean response spectrum. Nonlinear dynamic analysis results indicate that the maximum displacements of structures installed with supplemental dampers designed in accordance with the proposed method agree well with the given target displacements. The advantage of the presented procedure over the conventional iterative design method is also highlighted.

• 한국군사과학기술학회지
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• 제8권3호
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• pp.73-82
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• 2005

This paper describes shock waveform synthesis methods for a shock response spectnlm over a short time interval with which intereference between parts within a test item is increased to perform a sufficient shock test for damage or malfunction which may be caused by the interference between parts, and a digital filter for obtaining a shock response history required for the shock waveform synthesis and a digital inverse filter for restoration by inversely using the digital filter. The time at which the maximax value occurs in the response history is detected in order to establish a delay time which is one of the parameters in the wavelet, on the condition that the natural frequency of SDOF system with a Q (quality factor) of 10 equals to the wavelet frequency of the zero delay wavelet input. A shock response spectrum over a short time interval and an abrupt change in the acceleration for an instant are illustrated as features of the synthesized waveform.

• 한국구조물진단유지관리공학회 논문집
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• 제23권5호
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• pp.13-22
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• 2019

본 연구는 지진계측시스템이 설치되지 않은 중소형 교량의 지진손상 수준을 평가하기 위하여 대상 중소형 교량 인근에 위치한 지진관측소의 지진관측 데이터를 이용하여 대상 교량위치에서의 지반응답스펙트럼을 추정하기 위한 알고리즘을 제시하였다. 일반적으로 중소형 교량의 내진설계 및 성능평가는 동적해석법 중 응답스펙트럼해석법이 가장 널리 활용되고 있으므로 대상 중소형 교량에 대한 평가 지진력으로 지반응답스펙트럼을 적용할 수 있는 알고리즘을 제시하였으며, 제안된 알고리즘을 이용한 프로그램 알고리즘도 제안하고 제안된 알고리즘을 통하여 실제 지진계측데이터를 이용하여 특정 위치에서의 지반응답스펙트럼 추정 예를 나타내었다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.113-124
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• 2006

Despite the site classification method was improved in the previous study, the response spectrum would be required to be modified by adjusting the integration interval to calculate the site coefficients because the response spectra did not match well the average spectral accelerations obtained by site response analyses in the range of long periods. In this paper, new response spectra for each site categories were determined by adjusting the integration interval of long-period site coefficient $F_{v}$ from $0.4{\sim}2.0$ to $0.4{\sim}1.5$ second. It matched well the average spectral accelerations and new response spectrum, and it was also improved compared to the current site classification system.

• 한국소음진동공학회논문집
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• 제15권6호
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• pp.652-659
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• 2005

In this paper, seismic qualification analysis for the Plant control Panel is carried out to confirm the structural integrity under the seismic conditions represented by required response spectra(RRS). The finite element method(FEM) is used for the analysis and a mode combination method is adopted to obtain a more reliable spectrum analysis results. In addition, the experimental analysis is performed to compare the reliability of the analytical results. The analysis results shows that the plant control panel system is designed to have the dynamic rigidity with no resonance frequency below 33 Hz. The analytically calculated maximum stress of the plant control panel system is $36\%$ of the field strength of material, thus it can be shown that the system has a stable structure for the seismic load.

• Earthquakes and Structures
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• 제3권1호
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• pp.59-81
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• 2012

A ductility inverse-mapping method for SDOF systems including passive dampers is proposed which enables one to find the maximum acceleration of ground motion for the prescribed maximum response deformation. In the conventional capacity spectrum method, the maximum response deformation is computed through iterative procedures for the prescribed maximum acceleration of ground motion. This is because the equivalent linear model for response evaluation is described in terms of unknown maximum deformation. While successive calculations are needed, no numerically unstable iterative procedure is required in the proposed method. This ductility inverse-mapping method is applied to an SDOF model of bilinear hysteresis. The SDOF models without and with passive dampers (viscous, viscoelastic and hysteretic dampers) are taken into account to investigate the effectiveness of passive dampers for seismic retrofitting of building structures. Since the maximum response deformation is the principal parameter and specified sequentially, the proposed ductility inverse-mapping method is suitable for the implementation of the performance-based design.

• 한국기계가공학회지
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• 제19권4호
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• pp.45-51
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• 2020

In this study, a response spectrum analysis of an electric distributing board (EDB) was conducted to investigate seismic integrity in the design stage. For the seismic analysis, the required response spectra of a safe shutdown earthquake with 2% damping (RRS/SSE-2%) specified in GR-63-CORE Zone 4 was used as the ground spectral acceleration input. A finite element method modal analysis of the EDB was also performed to examine the occurrence of resonance within the frequency range of the earthquake response spectrum. Furthermore, static stress caused by deadweight was analyzed. The resultant total maximum stress of the EDB structure was calculated by adding the maximum stresses from both seismic and static loads using the square root of the sum of the squares (SRSS) method. Finally, the structural safety of the EDB was investigated by comparing the resultant total maximum stress with the allowable stress.

• 한국가스학회지
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• 제14권6호
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• pp.44-50
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• 2010

내진 평가에서 동적 해석이 필요한 원심펌프에 대하여, 시간 이력 해석에 비해 간편한 스펙트럼 해석을 이용하여, 진동 응답을 산출하였다. 유한요소법에 의하여 모드 해석을 하였으며, 모드 해석 결과에 입각하여 스펙트럼 해석을 수행하였다. 스펙트럼 해석에 의해 구해진 진동 응답은 시간 이력 해석의 결과보다 보수적으로 산출되어 안전하게 설계할 수 있음을 알 수 있었다. 본 연구에서의 펌프는 IEEE 344-1987에서 요구되는 조건에 따라 내진 구조 건전성이 평가 되었다. 각 부재의 최대 응력은 허용 응력이하로 산출되었으며, 펌프는 주어진 지진 입력에 대하여 요구되는 안전 조건을 구비하고 있음이 판명되었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.71-78
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• 2005

In performance-based design methods, it is clear that the evaluation of the nonlinear response is required. The methods available to the design engineer today are nonlinear tim history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. The nonlinear time analysis is the most accurate method in computing the nonlinear response of structures, but it is time-consuming and necessitate more efforts. Some codes proposed the capacity spectrum method based on the nonlinear static analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. The nonlinear direct spectrum method is proposed and studied to evaluate nonlinear response of structures, without iterative computations, given by the structural linear vibration period and yield strength from the pushover analysis. The purpose of this paper is to compare the accuracy and the reliability of approximate nonlinear methods with respect to RC dual system and various earthquakes.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.439-446
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• 1998

One of the most important roles in the nonlinear dynamic structural analysis is to select a proper ground excitation, which dominates the response of a structure. Because of the lack of recorded accelerograms in Korea, a stochastic model of ground excitation with various dynamic properties rather than recorded accelerograms is necessarily required. If all information is not available at site, the information from other sites with similar features can be used by the procedure of seismic hazard analysis. Eliopoulos and Wen identified the parameters of the ground motion model by the empirical relations or expressions developed by Trifunac and Lee. Because the relations used in the parameter identification are largely empirical, it is required to apply the artificial neural networks instead of the empirical model. Additionally, neural networks have the advantage of the empirical model that it can continuously re-train the new recorded data, so that it can adapt to the change of the enormous data. Based on the redefined traditional processes, three neural-networks-based models (FAS_NN, PSD_NN and INT_NN) are proposed to individually substitute the Fourier amplitude spectrum, the parameter identification of power spectral density function and intensity function. The paper describes the first half of the research for the development of Neural-Networks-based model for the generation of an Artificial earthquake and a Response Spectrum(NNARS).