http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이종마찰압접재 계면의 기계·금속조직학적 거동 및 파면특성 : STS304와 SM15C재를 중심으로 For STS304 and SM15C
오환섭,박경식,박준건,오정국,백영남 慶熙大學校 材料科學技術硏究所 1998 材料科學技術硏究論集 Vol.11 No.-
In this study is behavior of crack propagation and fracture under static tensile load, shear load, rotary bending fatigue load in friction welded dissimilar materials. Crack was observed in fine ferrite zone of SM15C and heat affected zone of STS304. Plastic flow was occured by friction welding process, so direction of crack is inclined with welded surface. Fatigue fracture most occurred in SM15C heat affected zone around interface. Fibrous zone with the view of macroscope and dimple pattern with the view of microscope were observed at fracture surface. Result is more metal micrstructure dependence than stress dependence by mechanical and metallic mechanics.
吳煥燮,結城良治 慶熙大學校 材料科學技術硏究所 1992 材料科學技術硏究論集 Vol.5 No.-
Stress analysis of surface crack tips becomes very important in the recent development of leak-before-break(LBB) concepts. In this study the stress intensity falter k analyzed by considering the fatigue fracfure process which is characterized by interface coalesence and growth. Criteion parameters derived from the stress intensity factor obtained from the boundary element method(BEM) are used to predict the fatigue life. We develop the surface crack growth analysis system using the stress intensity factor data base and also fatigue crack growth law. The results are obtained as some kind of fatigues.
오환섭,양인수 慶熙大學校 材料科學技術硏究所 1995 材料科學技術硏究論集 Vol.8 No.-
In this paper, stress intensity factor of a crack alone the straight interface between two dissimilar materials, one of the very important criterion in fracture mechanics, is analysed accurately using boundary element method(BEM). Stress intensity factors of a central interface crack in dissimilar materials, a central interface crack and a equal length parallel crack in dissimilar materials, and two neighbor interface cracks in dissimilar materials, are calculated. It is confirmed that the calculated values of the stress intensity factor for various interface cracks in finite plate and infinite plate are completely consistent with the previously reported results. Also, the effects of Young's modulus and interference of cracks on stress intensity factor are investigated.
오환섭,정효진,박상필,손두익 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-
The damage of the pressure courage by degradation can become the reason of unexpected break down or failure accident and it is very important because safety accident, the production loss, environmental pollution, social problems are occur. Consequently The result to investigat of failure accident for domestic pressure vessel, the factor of degradation is SCC, Sorrosion, Cavity, Crack
吳煥燮 慶熙大學校 1986 論文集 Vol.15 No.-
Low-carbon steel was chosen as the material for this experiment since it has clear fatigue limit as well as the reason that the defect in the structure of the material does'nt effect to the fatigue fracture. This study has been made to investigate into the behavior of fatigue limit, of fatigue crack initiation, and of fatigue crack propagation under the condition ol rotating bending stress; specifically on the independency of stress-field as well as the crack behavior of surface micro-hole defect(MHD), which it made artificially the specimen. The results obtained can be summarized as follow; Fatigue limit of specimen with MHD is defined as a critical stress which is needed for repropagation of the crack around MHD. The behavior of non-propagating crack which is positioned around the MHD is found to be double of the size of MHD. The effect of MHD with regard to the fatigue limit and size of critical defect(dc) are depended on hardness and ferrite grain size.
오환섭,최훈,박철희 慶熙大學校 材料科學技術硏究所 1995 材料科學技術硏究論集 Vol.8 No.-
In this study, to analyze Stress Intensity Factor of surface crack under arbitrarily distributed loads, influence function method was used. Influence coefficient K_(v), stress intensity factor of ith crack lead when the unit load is weighted on ith node in crack surface, was obtained by using the Boundary Element Method which is known as superior to Finite Element Method in fracture mechanics. In boundary element analysis in fracture mechanics, Kelvin's and Mindlin's solutions were used as a fundamental solution and displacement extrapolation method was used to determine stress intensity factor. Various shapes of surface crack were analyzed and obtained solutions corresponded well to known solutions. Stress intensity factors were calculated. Effectively by using the stress distribution on crack surface and influence coefficients.
吳煥燮,金政泰 慶熙大學校 材料科學技術硏究所 1994 材料科學技術硏究論集 Vol.7 No.-
In this study stress intensity factor, one of the very important parameter in LEFM, is analysed economically and accurately, using boundary element method(BEM) which is known as superior in Fracture, mechanics. Therefore stress intensity factor K_(1) of circular inner crack in infinite region and elliptical surface crack on the surface of finite rectangular block, both subjected to uniform tension, are calculated by BEM. In addtion to Kelvin's solution, Mindlin's solution is used as a fundamental solution and Barsoum's quater point crack tip element is adopted. In order to obtain stress intensity factor, extrapolation method is used and regression coefficient is adopted as an objective standard. P.C. is used as computing machine and comparing BEM results with exact solution and already published results, very accurate results are obtained economically.
오환섭,김시현,김성재,양인수 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.6
Applications of brazing in the studying fields such as high-speed machining are very increasing in various industry fields. Therefore, applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem dissimilar materials in brazed interface. In this study, stress intensity factor(SIF) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a hardmetal and a HSS by two dimensional(2-D) BEM. Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine SIF.