• 한국해양공학회지
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• 제9권2호
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• pp.186-192
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• 1995

This paper investigates the problem of random analysis of fixed structures which are influenced by waves and current. Morison eqution was employed to deal with the wave and current load. The wave kinematics are randomly generated from the wave spectrum. The necessary statistics are calculated from the resulting response time history. The simulation results are turned out to be very sensitive to the simulation technique.

• 한국지진공학회논문집
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• 제21권4호
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• pp.197-204
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• 2017

This paper aims to analyze the economic feasibility and investigate the possibility of elastic seismic design of wind-designed highrise concentrically braced frames considering change of mechanical properties of Korean steel under the strong wind and the low seismicity in Korea. To this end, first, highrise concentrically braced frames were designed considering strong wind load. And then, analyses of the economics of them were performed. The seismic performance evaluation of wind-designed highrise buildings was conducted using the response spectrum analysis procedure. Analysis results show that it is possible to save up to approximately 90% of the amount of steel on the 10% increase in steel strength without serviceability. However, with serviceability, the design sectional area of the steel with relatively high strength tends to increment considerably because of the lateral stiffness due to reduction of the inertia moment and so on. This point might apply to limitation of the steel with high tensile yield strength.

• Earthquakes and Structures
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• 제15권2호
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• pp.203-214
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• 2018

Deflection control in tall buildings is a challenging issue. Connecting of the towers is an interesting idea for architects as well as structural engineers. In this paper, two reinforced concrete core-wall towers are connected by a truss bridge with buckling restrained braces. The buildings are 40 and 60-story. The effect of the location of the bridge is investigated. Response spectrum analysis of the linear models is used to obtain the design demands and the systems are designed according to the reliable codes. Then, nonlinear time history analysis at maximum considered earthquake is performed to assess the seismic responses of the systems subjected to far-field and near-field record sets. Fiber elements are used for the reinforced concrete walls. On average, the inter-story drift ratio demand will be minimized when the bridge is approximately located at a height equal to 0.825 times the total height of the building. Besides, because of whipping effects, maximum roof acceleration demand is approximately two times the peak ground acceleration. Plasticity extends near the base and also in major areas of the walls subjected to the seismic loads.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.632-637
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• 2012

Antenna equipment is transported being assembled to moving equipment and often subjected to vibration and shock excitation during transportation. In these circumstances, structural safety of antenna equipment must be secured. Wire rope isolators are assembled between moving equipment and antenna equipment to reduce the level of vibration and shock. In this paper, a isolator that are suitable to the system is selected and dynamic characteristics analysis of driving on antenna equipment is conducted using real system and the result is compared with response analysis. Also modal test of array-antenna pack-assembly is conducted and structural safety of that is secured by reinforcing its structure.

• 한국생산제조학회지
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• 제24권1호
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• pp.87-93
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• 2015

The dynamic responses of a telescope loaded on an STSAT-3 satellite were analyzed, and environmental tests were conducted to verify the reliability of the design. The space use telescope COMIS (compact imaging spectrometer) is a major payload of the STSAT-3 launched on November 21, 2013. Vibration responses such as the acceleration, displacement, and velocity with respect to random vibration and shock impulse inputs were obtained based on theoretical fundamentals in conjunction with finite element analysis. The main focus of this study was on developing technology for accurate and/or favorable modeling and analysis of the structure and fitting the results to that of experiments. Cutting-edge technology for manipulating the vibrations of a space use telescope is suggested.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.20-27
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• 1998

In the current seismic design codes design earthquake is usually defined as the earthquake with the 90 percent probability of not being exceeded in the life time of a structure which is assumed as 50 years equivalent to the earthquake with 475 year recurrence period. However the life time of tall building structures may be much longer than 50 yers. The current seismic design code requires the modal analysis or dynamic time history analysis for the buildings with the height exceeding a certain height limit. The objective of this study is to collect the earthquake ground motion(EQGM) which can be used for dynamic time history analysis for tall buildings. For this purpose linear elastic design response spectrum (LEDRS) in the code is scaled to account for the recurrence period of the design earthquake. The earthquake ground motions which has been recorded are calibrated to fit the scaled LEDRS. The set of calibrated EQGM can be treated as design EQGM for the design of tall building with longer lifetime than ordinary building.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.375-388
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• 2024

In this study, to evaluate the shock and vibration load characteristics of used fuel, a sea transportation test was conducted using simulated fuel assemblies under normal transport conditions. An overall test data analysis was performed based on the measured strain and acceleration data obtained from cruise, rotation, acceleration, braking, depth of water, and rolling tests. In addition, shock response spectrum and power spectral densities were obtained for each test case. Amplification and attenuation characteristics were investigated based on the load path. The load was amplified as it passed from the overpack to the simulated used fuel-assembly. As a result of the RMS trend analysis, the fuel-loading position of the transportation package affected the measured strain in the fuel rod, and the maximum strains were obtained at the spans with large spacing. However, even these maximum strains were very small compared to the fatigue strength and the cladding yield strength. Moreover, the fuel rods located on the side exhibited a larger strain value than those at the center.

• 한국소음진동공학회논문집
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• 제13권5호
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• pp.334-340
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• 2003

Exponential window function Is widely used In impact hammer testing to reduce leakage error as well as to get a good S/N ratio. The larger its decaying rate is, the more effectively the leakage errors are reduced. But if the decay rate of the exponential window is too large, the FRF is distorted. And the modal parameters of the system can not be exactly identified by modal analysis technique. Therefore, it is a difficult problem to determine proper decay rate in impact hammer testing. In this paper, amount of the FRF distortion caused by exponential window is theoretically uncovered. A new circle fitting method is also proposed so that the modal parameters are directly extracted from impulse response spectrum distorted by the exponential-windowed impulse response data. The results by the conventional and proposed circle fitting method are compared through a numerical example.

• Earthquakes and Structures
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• 제11권5호
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• pp.741-777
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• 2016

A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

• 인간행동과 음악연구
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• 제21권1호
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• pp.69-87
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• 2024

본 연구는 자폐스펙트럼장애(Autism Spectrum Disorder, 이하 ASD) 아동을 대상으로 음악적 단서 및 후속 자극에 따른 공동주의 반응 행동이 달라지는지 알아보고, 비장애(neurotypically developing, 이하 NT) 아동 그룹과 비교하는 실험연구이다. 본 연구의 대상자는 만 3세에서 5세 사이의 ASD 아동 13명과 NT 아동 14명이다. 본 연구에서는 공동주의 반응을 유도하는 단서(음악적 단서 대 언어적 단서)와 아동의 공동주의 반응 행동에 대한 후속 자극(언어 자극 대소리 자극 대 음악 자극)을 구성하고 총 6가지 과제 조건을 2회씩 총 12회 제시하였다. 먼저, 주의 유도 단서를 제공하고 3초 이내 대상자의 주의 전환을 평가하였고 대상자의 공동주의 반응 행동이 나타난 경우, 후속 자극을 제공하였으며 후속 자극을 제공하는 동안 대상자의 사회적 참조 행동의 발생 빈도를 측정하여 비교 분석하였다. 연구 결과, 주의 유도 단계에서는 음악적 단서를 제공했을 때 ASD 아동의 공동주의 반응 행동 수준을 높게 유도하는 것으로 나타나 선행연구와 일치한 결과를 보였다. 이어 후속 자극 제공 단계에서는 음악 후속 자극이 ASD 아동의 사회적 참조 행동의 빈도를 증가시킨 것으로 확인되었다. 이는 음악 후속 자극이 단서로서의 감각자극에서 나아가 대상자로 하여금 타인의 사회적, 정서적 정보를 이해하고 반응하도록 유도하는데 그 적용 범위가 확장된 것에 의의가 있다. 또한, ASD 아동의 공동주의 행동 이후 제공하는 후속 음악 자극이 효과적인 사회적 강화 요인이 될 수 있음을 시사한다.