경사충돌이 탄소섬유강화 적층쉘의 특성에 미치는 영향

김영남,조영재,양광영 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.2

최근 탄소섬유 강화 플라스틱(이하CFRP)는 금속재료에 비해 비강도 및 비강성이 우수하여 우주항공분야에서 널리 사용되고 있다. 본 연구에서는 복합재 적층웰의 곡률과 적층방향에 따른 관통특성을 고찰하고자 한다. 또한, 경사충돌을 적용하여 복합재 적층웰의 관통특성을 연구하였다. 시험편의 적층구성은 [0₃/90₃)_(s), [90₃/0₃]_(s) 와 [0₂/90₃/0]_(s), [90₂/0₃/90]_(s) 2계면구조와 4계면 구조로 적층하였으며 다양한 곡률반경 (R= 100, 150, 200mm 와 ∞)을 적용하였다. 실험 방법으로는 강구를 시험편에 횡방향으로 관통시켰으며, 두 개의 ballistics-screen에서 강구가 통과한 시간의 전 · 후를 측정한 후 속도를 계산하였다. 그 결과 임계관통 에너지는 계면의 수가 적고 충격면의 경사각도가 커질수록 증가하였다. 또한. [0₃/90₃]_(s) 와 [0₂/90₃/0]_(s) 시험편이 [90₃/0₃]_(s) 와 [90₂/0₃/90]_(s) 시험편보다 임계관통에너지가 더 높게 나왔다. Currently, carbon-fiber reinforced plastics(CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and stacking sequence on the penetration characteristics of composite laminated shell. And were performed to investigate the penetration characteristics of composite laminated shells by the oblique impact. They are stacked to [0₃/90₃]_(s), [90₃/0₃]_(s) and [0₂/90₃/0)_(s), [90₂/0₂/90)S their interlaminar number two and fore. They are manufactured to varied curvature radius (R= 100.150,200mm and ∞). When the specimen is subjected to transverse impact by steel ball. the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistics-screen sensor located a known distance apart. In general, the critical penetration energy interface decrease and slope angle on the impact surface increased. [0₃/90₃]s and [0₂/90₃]_(s) specimens higher than [90₃/0₃]_(s) and [90₂/0₃/90]_(s) specimens.

CFRP적층쉘의 적층구성 및 곡률반경에 따른 관통특성

임광희,조영재,이길성,심재기,김영남,양인영 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

최근 탄소섬유 강화 복합재료(이하 CFRP)는 비강도, 비강성이 높아 경량화가 요구되는 우주항공분야에서 구조용 재료로 널리 이용되고 있다. 본 연구에서는 CFRP 적층쉘의 적층구성 및 곡률반경에 따른 관통 특성을 고찰 하고자 한다. 실험에 사용된 복합재료는 일방향 프리프레그시트로서 적층방법은 〔0₃/90₃〕, 〔0₂/90₂〕s,와 〔0₂/90₃/0〕s, 〔0/90₂/0〕 2계면과 4계면으로 적층하였다. 그리고 다양한 곡률 반경을 적용하였다. (R= 100, 150, ∞). 적층순서에 맞게 적층된 시험편은 경화온도 130℃에서 진공백 성형과정을 오토클레이브로 제작 하였으며 100x140mm 크기로 절단 하였다. 시험편은 강구로 관통시켰으며 ballistic-screen sensor로 속도를 측정하여 충격전 운동에너지와 충격 후 운동에너지를 구할 수 있다. 흡수에너지는 곡률이 커질수록 증가하였으며 4계면 시험편보다 〔0₃/90₃〕s 와 〔0₂/90₂〕s 적층구조를 갖는 2계면 시험편이 흡수에너지가 더 높게 나왔다. Currently, carbon-fiber reinforced plastics (CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and staking sequence on the penetration characteristics of CFRP laminated shell. Composite laminates used in this test are CFRP orthtropic laminated plates, which are stacked with two-interfaces 〔0₃/90₃〕s, 〔0₂/90₂〕s and 〔0₂/90₃/0〕s. 〔0/90₂/0〕s. They are manufactured to varied curvature radius (R= 100. 150, 200 mm and ∞). They are cured by heating to the appropriate hardening temperature(130℃) by mean of a heater at the vacuum bag of the autoclave. Test specimens were prepared with dimensions 100mmx140mm. When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistic-screen sensor located a known distance apart. Absorbed energy increased as the curvature increased. 〔0₃/90₃〕s and [0₂/90₂〕s specimens, which is small interlaminar number, was higher than fore interlaminar specimen.

ACP 실증에 따른 시설 주변 주민피폭선량 평가

김성영,정운관,윤인식,심재학 조선대학교 에너지.자원신기술연구소 2003 에너지·자원신기술연구소 논문지 Vol.25 No.2

The Advanced spent fuel Conditioning Process(ACP) is under development for the effective management of spent fuel which had been generated in nuclear plants. The ACP needs a hot cell where most operations will be performed. To give priority to the environment safety, radiation doses evaluation for the radioactive nuclides was preliminarily performed with the basic concept design report, the meteorological data and the recent site specific data. According to the production and release rate of nuclides, dose evaluations for residents around facility were performed. The evaluation result shows a safe margin for regulation limits and SAR limit of IMEF where this facility will be constructed.

휘발성유기화합물의 배출원 구성물질 성분비에 관한 기초 연구

이영재,이학성,강병욱,신대윤 한국환경과학회 2003 한국환경과학회지 Vol.12 No.4

The purpose of this study was to develop the preliminary source fingerprints of volatile organic compounds(VOC). The source categories studied were vehicles, gasoline vapor, gasoline storage tank, coating, dry cleaning and road covering. The source samples were collected using 6L electro-polished stainless steel canisters for about 20 seconds. From this study, the main component emitted from VOC sources in Korea was toluene. The toluene proportion for road covering, vehicles, coating and gasoline vapor were 35, 18, 16 and 5%, respectively, The C_2-C_5 alkane and alkene compounds were mainly emitted from vehicles, gasoline vapor and gasoline storage tank, The main compounds of coating were m/p-xylene(34%), toluene(16%), 1,2,4-TMB(22%) and 1,3,5-TMB(13%) were mainly emitted.

고온을 받은 콘크리트의 공학적 특성

권영진,김용로,장재봉,김무한 한국화재소방학회 2004 한국화재소방학회논문지 Vol.18 No.1

본 연구는 잔골재 및 혼화재 종류, W/C에 따른 콘크리트의 폭열성상 및 압축강도 초음파속도 등의 공학적 특성을 검토함으로서 폭열 방지 및 화재 피해를 입은 콘크리트 구조물의 재사용과 보수보강, 안전도평가 등에 기초적인 자료를 제시하고자 한다. 폭열성상을 살펴보면, 잔골재에 따라서는 바다모래를 사용한 경우 폭열이 발생하지 않았거나 약간의 폭열이 나타나는 정도이나 재생잔골재나 부순모래를 사용한 경우에는 폭열이 심하게 나타났다. 또한 혼화재 종류에 따라서는 대체로 유사한 폭열성상을 나타내었다. 한편, W/C 30.5%의 고강도 영역에서는 대부분 폭열하였으나 W/C 55%의 보통강도 영역에서는 대부분 폭열하지 않았다. 잔존 압축강도는 W/C 55%의 경우 평균 45%로 나타났으며, W/C 30.5%의 경우에는 평균 6fl%로 나타났다. 초음파속도는 잔골재 종류 및 W/C, 가열시간에 따라 다르게 나타났으며, 가열후 3개월이 가열후 1개월보다 악 1.3-8.4%의 초음파속도 회복을 보였다. The purpose of this study is to present data for the reusing, rehabilitation and estimation of safety of RC structure damaged by fire, and for the prevention of explosive spalling by investigation the properties of explosive spalling, compressive strength and ultrasonic pulse velocity according to kinds of fine aggregate, admixture and water-cement ratios. In explosive spalling properties with kinds of aggregate. explosive spalling does not appear or little at surface in the case of used sea sand, but the case (of using recycled sand or crushed sand is worse and worse. Property with the kind of admixture does not appear specially. And high strength concrete with W/C 30.5% was taken spalling, but 55% does not appear. It is found that residual compressive strength after exposed at high temperature showed 45% in W/C 55%, and 64% in W/C 30.5% of its original strength averagely. Ultrasonic pulse velocity is different with kinds of aggregate, W/C, and heating time. When 3 month age after heating ultrasonic pulse velocity is recovered abut 1.3%-8.4% of its 1 month age after heating.

Si 기판 위에 CeO_2 유전체 박막 성장

한재원,김상훈,한영기,최무용 성균관대학교 기초과학연구소 1994 論文集 Vol.45 No.1

CeO_2 single target을 사용하여 on-axis rf magnetron 스퍼터링 방법으로 Si(100) 단결정기판 위에 CeO_2 유전체 박막을 성장시킬 때 기판온도, 산소 부분압력, rf input power, 두께 등의 성장변수들이 박막 성장에 미치는 영향을 조사하여 (ℓ00) 방향 in-situ 성장의 적정조건을 찾는 연구를 하였다. 각기 다른 조건에서 제조된 박막의 X-ray 회절 방법에 의한 구조 분석과 SEM(Scanning Electron Microscopy)에 의한 표면의 미세 구조 분석을 통하여 그 특성을 조사한 결과 기판 온도, 산소 부분압력, rf input power 세기, 박막의 두께가 박막 성장에 결정적인 영향을 미치는 중요 성장 변수임을 확인하였다. CeO_2 박막은 target과 기판사이 거리 50㎜, 총압력 30mTorr일 때 기판 온도 800℃, 산소 부분압력 3 mTon, power 90 W(이때 성장속도 0.83Å/s), 성장시간 2시간(이때 두께 500Å)일 때(ℓ00) 방향으로 잘 성장되는 것을 발견하였다. We have studied systematically the optimum condition for in-situ perparation of CeO_2 thin film on Si(100 substrate by single-target rf-magnetron sputtering method. We examined effects of the substrate temperature, oxygen partial pressure, rf input power, and thickness by studying X-ray diffraction patterns and photographs of scanning electron microscopy of the grown films. We found that all of these parameters influence decisively on the struture of the grown films. We also found that the CeO_2 thin film grows well at∼800℃ of the substrate temperature, 3 mTorr of the oxygen partial pressure, 90 W of the rf input power(corresponding to 0.83Å/s of the deposition rate), and 5000 Å of the thickness for the total sputtering gas of 30 mTorr and the sputtering target of 2 inch diameter used.

화재피해를 입은 콘크리트의 공학적 특성에 관한 실험적 연구

권영진,김무한,김용로,장재봉 대한건축학회 2005 大韓建築學會論文集 : 構造系 Vol.21 No.1

A fife outbreak in a reinforcement concrete structure looses the organism by the different contraction and expansion of hardened cement pastes and aggregate, and cause" cracks by thermal stress, leading to the deterioration of the durability So concrete reinforcement structure is damaged partial or whole structure system Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration In general concrete structures Fundamental information and data on the properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration In this study, normal and high strength concrete were exposed to a high temperature environment And than fundamental data for the character change of concrete heated highly were presented by measuring characters of explosive spalling, ultrasonic pulse velocity and compressive strength before and after heating It is intended to present data for the exact diagnosis and selection of rep31r and reinforcement system of the deteriorated concrete heated highly

교육과정 분야에서의 질적연구

김영천,조재식 한국교육인류학회 2001 교육인류학연구 Vol.4 No.3

상 분리 모선 시스템에서의 자계 및 와전류 특성 해석

심재학,정운관,윤인식,김성영 조선대학교 에너지.자원신기술연구소 2003 에너지·자원신기술연구소 논문지 Vol.25 No.2

In the analysis of isolated phase bus bar(IPB), the magnetic field distribution generated by large current must be understood accurately. Especially, while the current of bus conductor is flowing, almost the same amount of current as the current of bus conductor is induced in the enclosures under the influence of time varying magnetic field, and the large electric loss and the deterioration of insulating capability might occur due to Joule heating effect. Therefore the optimal design of IPB satisfying the condition of minimizing the electric loss, the magnetic field distribution and eddy current characteristics around the enclosures must be analysed accurately. In this paper, the magnetic field distribution and the eddy current characteristics of three phase isolated phase bus have been studied along the phase angle by comparing the effect of eddy current on the magnetic field distribution with the case that eddy current is not considered, and also the effect of material thickness and radius of enclosure on the eddy current distribution is discussed. In the analysis of time varying magnetic field, instead of finite difference method(FDM) which is generally used, finite element method(FEM) with phasor concept is investigated under the assumption that the bus current is purely sinusoidal. The characteristics

韓方用 脈 檢出시스템

이호재,박영배,김진우,허 웅 明知大學校 産業技術硏究所 1992 産業技術硏究所論文集 Vol.11 No.-

This paper describes a design of trasducer for non-invasively detecting pressure radial pulse wave in aterial system and a recording system that for the striding the aterial pulse diagnosis of korean traditional medicine. The mechanism of transducer is composed of sensing mechanism, pressure sensor, conditioning amplifier. The variation of radial pulse pressure in the sensing mechanism is converted to the electric signal by piezo-resistive pressure sensor and it converted to the digital signal after preprocessing via A/D converter. The converted signals inputed to the computer as data files and then it display to the monitor for waveform watching and this datas can be used as the aterial pulse diagnosis data. This system effectively detect non-differential radial pulse wave and we conside that if analizing the recorded radial pulse wave, compared each other, it can be helpful in quantify radial pulse wave diagnosis of the Korean traditionl medicine.