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곽진성(Kwak Jinsung),오진호(Oh Jinho),이종민(Lee Jong-min) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
In this paper, hydraulic mass is estimated by numerical method which simulates experiments in which the fluid dynamic forces acting on perforated plates vibrating in water. In the experiments, natural frequency of rigid plates with regularly aligned holes in air was compared to that of the same plates in water. From the results, hydraulic mass was estimated and formulated in dimensionless form. But the frequency was solved from simple harmonic oscillation, the result was limited to apply to solve problems related to plates flexibility. In this paper, hydraulic mass expressed in terms of added mass is estimated in the same way of the test and it is expanded to flexible plate which has a variety of hole shapes. Acoustic element is used to reflect the effect of water. The results are validated by comparing natural frequencies between with the added mass and with the acoustic element.
다중 압력 스펙트럼 밀도를 이용한 감쇠 탱크 구조 건전성 평가
곽진성(Kwak Jinsung),정민규(Jung Min-kyu),오진호(Oh Jinho),이종민(Lee Jong-min) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
The main purpose of PCS(Primary Cooling System) is to remove heat generated from the reactor core through the heat exchangers. The coolant passing through the reactor core contains a variety of radionuclides. N-16 governs the coolant radioactivities at the core exit, but it has a very short decay time. The main function of decay tank is to decay the readionuclides, especially N-16 by providing enough transient time to ensure that N-16 activity decreases in the decay tank. The decay tank has three internal perforated plates which spread the coolant into the whole section of the decay tank to increase transit time. The perforated plate is affected by various loadings such as seismic load, thermal load, flow induced vibration and etc. Specially, the pressure induced by flow gives the main effect to the structure integrity of the perforated plate. In this paper, structure integrity of decay tank including fatigue is evaluated through the pressure power spectral density functions that are derived from turbulent flow.
곽신영 ( Kwag Shinyoung ),임승현 ( Eem Seunghyun ),곽진성 ( Kwak Jinsung ),오진호 ( Oh Jinho ) 한국복합신소재구조학회 2020 복합신소재구조학회논문집 Vol.11 No.1
최근 국내에서 발생한 경주지진 및 포항지진이 도심지 및 원자력발전소 주변에서 발생함에 따라 인근 주요 구조시스템에 피해를 발생시킨 바 있다. 이에 따라, 본 연구는 원전 배관계통의 지진 거동 특성을 실험 및 해석적으로 규명하고, 이를 바탕으로 내진성능을 평가하는 연구를 수행하는 것을 목적으로 한다. 이를 위하여, 원전 배관계통을 대상으로 한 진동대 시험 결과를 바탕으로 배관 수치해석 모델을 수립하고 이를 시험 결과를 통하여 검증한다. 또한, 이러한 검증된 수치해석모델을 기반으로 배관계통의 내진성능을 평가한다. 수치해석 모델 검증 결과, 수립된 수치모델의 고유진동수, 감쇠비 및 변위 응답이 진동대시험 결과와 유사한 것으로 나타났다. 이러한 검증된 수치모델을 바탕으로 평가된 내진성능 값은 기존 원전 배관의 내진성능 값의 범위와 비교적 유사한 값으로 평가되었다. 이는 설계기준지진을 크게 상회하는 값이지만, 원전 주요 기기 임을 감안할 때 추가적인 내진성능 상향이 확보되면 원전 지진 안전성 향상에 많은 기여를 할 수 있을 것으로 판단된다. 본 연구의 결과는 추후 원전 배관계통 내진성능평가를 위한 정량적인 자료로 활용이 가능할 것으로 판단된다. The recent earthquakes in Gyeongju and Pohang have damaged the major local structures and buildings since they occurred in urban areas and near nuclear power plants. Thus, this study aims to reveal, experimentally and analytically, the earthquake behavior of the piping systems of nuclear power plants and to assess their seismic performance. Based on shaking table test results, the numerical analysis model of a piping system was developed and validated; then, it was used to assess its seismic performance. The validation showed that the fundamental frequency, damping ratio, and displacement response of this numerical model were consistent with the shaking table test results. In addition, the seismic performance estimated by using this model was relatively similar to the performance range of existing nuclear plant piping systems. Thus, these results of this study could serve, in future studies, as quantitative data for assessing the seismic performance of piping systems in nuclear power plants.