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탄소섬유/에폭시 복합재료의 잔류강도 저하해석에 의한 피로수명 평가
심봉식,성낙원,옹장우 대한기계학회 1991 대한기계학회논문집 Vol.15 No.6
본 연구에서는 피로 잔류강도저하(fatigue residual strength degradation) 개념을 이용하여 복합재료의 잔류강도와 피로수명을 예측하고 실험을 통하여 비교 평 가하였으며, 설계시 고려되어야 할 인자를 파악하여 파손방지를 위한 유한 수명설계 및 손상허용설계의 기본자료를 집적함으로서 새로운 소재인 탄소섬유 강화 복합재료의 신뢰성 향상을 위한 개발과 고강도 경량화를 위한 이용설계에 활용할 수 있도록 하는 데 그 목적이 있다. Fatigue tests have been carried out to measure the degradation of the residual strength and the fatigue life in carbon/epoxy (0/45/90/-45)$_{2s}$ composite materials. Theoretical predictions of residual strength and fatigue life were compared with experimental results. Distribution characteristics were studied using the probability of failure based on the cumulative distribution function and median rand. The static ultimate strength of carbon/epoxy composites used herein is observed to be relatively higher than that of existing similar composites ; while fatigue life is shorter due to the brittleness of matrix. The fatigue life obtained in these experiments is shorter than that estimated by residual strength degradation model when the stress level above 0.6 For the stress level of 0.6, the experimental value was abruptly increased. The cumulative distribution function for the static ultimate strength is well correlated to that for the strength converted from the measured fatigue life. Also, the predicted distribution of residual strength shows good agreement with the experimental results. Therefore, it is proven that the residual strength degradation model is reasonable.e.
AISI 4340 ?? 鋼의 衝擊에너지와 ??값 사이의 相互關係에 관한 硏究
성낙원,심봉식 東亞大學校 大學院 1986 大學院論文集 Vol.11 No.-
Charpy V-notch impact test and compact tension test in the enviroment of high and low temperature on the specimens of N?C?M? steel have been conducted. This paper is to evaluate the correlation between CVN and K? test results as a function of temprature. The results of this study are as follows. 1. The transition temperature by the effect of impact absorption energy from lower shelf to upper shelf have the tendencies of increasing with the incrase of temperature. 2. The value of K? measired from compact test is linearly increased with the increase of temperature. 3. The empirical correlation between impact energy and value of K? is obtained as K?/E=3.2545(CVN)-5.0064 and the rates of the erro from the test results are within 7pe cent.
炭素纖維强化 複合材料의 機械的 强度特性 및 疲勞壽命豫測에 관한 硏究
成洛元,沈奉植 동아대학교 공과대학 부설 한국자원개발연구소 1993 硏究報告 Vol.17 No.1
An experimental investigation was performed on the carbon-epoxy resin composite materials under constant stress amplitude and two step loading high low type and low high type loading, to study the mechanical properties and fatigue properties. Different shape of test specimen and test methods were used for evaluating the dispersion pattern in fatigue life and its reliability. A statistical approach was applied to test data with the aid of two parameter Weibull probabilities. It is indicated that the dispersions in the fatigue life are more wider at the high stress amplitude than at the low stress level and fatigue life was extended in the two step loading. Experimental data for the fatigue life showed good agreement with the one of the theoretically predicted at high stress level.
박근옥,심봉식 한국경영과학회 1998 한국경영과학회 학술대회논문집 Vol.- No.1
To research human factors, we developed KAERI-HMS having the design features of fully VDU based control room environment. The plant control and monitoring actions can be performed by clicking an icon displayed on the touch screen CTR and FPDU. This paper describes several design issues and problems found during HMS acceptance test.
WEL-TEN60 母材와 熔接材의 低溫 引張 및 衝擊特性에 關한 硏究
金載勳,沈奉植,邕章祐 忠南大學校 産業技術硏究所 1987 산업기술연구논문집 Vol.2 No.2
This study was aimed to determine tensile and impact properties of base and weld metals of WEL-TEN60 of temperatures from-70℃to 70℃. It is particularly important to assess tensile properties, absorbed energy change, lateral expension ratios and fracture appearance in order to prevent brittle fracture of this material at low temperatures. The obtained results were as follow: In case of base metal, the ultimate tensile strength, yield strength and elongation increase as the temperature decreases. The weld metal showed almost the same reactions as the base metal did. The fracture morphology of base and weld metals was that of dimple fracture at all temperature ranges. The dimple size got smaller as the temperature decreased. The fact that as the temperature increased, the absorbed energy increased seemed due to the increase of loading time. The curves of fibrous fracture, lateral expansion and absorbed energy kept almost the same shape. We came to conclusion that when we applied 15 ft-1b CVN temperature, the materials are safe from brittle fracture over-70℃.
AISI 4340鋼의 引張特性 및 破壞靭性에 미치는 溫度의 影響에 관한 硏究
성낙원,심봉식 동아대학교 공과대학 부설 한국자원개발연구소 1991 硏究報告 Vol.15 No.1
The K_(IC) value derived from CVN test were considerably different from measured value and it was difficult to predict the correct K_(IC) value of the materials under consideration. Compact tension and Charpy V―notch test in the invironment of high and low temperature on the specimen of AISI4340 steel have been conducted. The results may be sumerized as follows. The transition temperature by the impact absorbation energy range from - 50℃ and 150℃ and the impact energy from lower and high shelf have a tendencies of increasing with increase of the temperature. The measured K_(IC) value from CT test linearly increased with the increase of temperature. The K_(IC) value from the test fomular were derived and the error are within 6.8% against measured K_(IC) value.
炭素纖維强化積層材의 破壞靭性에 대한 노치形狀 및 溫度의 影響에 關한 硏究
邕章祐,沈奉植,吳在脅 忠南大學校 産業技術硏究所 1989 산업기술연구논문집 Vol.4 No.2
An experimemtal study was carried out on the effect of notch radius, notch length, stacking sequence, notch orientation, specimen thickness and temperature to the fracture toughness of carbon / epoxy laminates. the fracture toughness is decrease with an increase of notch radius, notch length, temperature and specimen's thickness and the fracture toughness of the(0°/±45°/90°)s laminates is higher than the (0°/45°/90°/-45°)s laminates and 90°notch orientation is higher than 0°notch. Also, it is assumed that the effects of temperature are related with specimen's curing cycle temperature.