http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
複合組織鋼의 低 및 高 사이클 疲勞特性에 관한 硏究(Ⅱ) : 高사이클 疲勞特性
成洛元 東亞大學校 大學院 1988 大學院論文集 Vol.13 No.-
In this study, a series of experiments on the dual phase steel with different grain size are performed to investigate high cycle fatigue properties. Specimen of SM 20C steel, matrix material and the dual phase steel consisting of three different sized grains were subjected to a series of high cycle fatigue test. The crack propagation rate in the high cycle fatigue region also has been examined taking in to consideration of crack closure effect. The test results in high cycle region show that the propagation rate in most range of stable crack propagation, second stage, are linealy aranged by using the effective stress intensity factor range. Dual phase steel are superior to SM 20C steel in fatigue limit and has longer fatigue life. The ratio of fatigue propagation life and fatigue limit are decreased as it approches to the value of fatigue limit. The aspect ratio of the surface crack length and the depth show constant slope between 0.68 and 0.78. The curve of U, the ratio of effective stress intensity factor range versus crack length show an asymptote to the constant value as the crack length increase. Through above mentioned experimental results, it is also found that the crack propagation rate is quite dependent to the crack length and stress amplitude in the local range. And fatigue life of the dual phase steel in the region of stable crack propagation could be predicted in term of effective stress intensity factor range.
축방향의 압축하중을 받는 얇은 원통 "쉘"의 좌굴에 관한 실험적 연구
成洛元 東亞大學校 大學院 1981 大學院論文集 Vol.5 No.-
An experimental study of the buckling of thin cylindrical shell under the axial compression was carried out. Buckling procedure were obserbed and the results obtained for the buckling stress were compared with theoretical value and approximate soulution of the exisiting literature. The test model of aluminum alloy were used. From this study, the results are as follows; Buckling behavior is a dynamic procedure combinded with potential change due to the bending energy stored by the successive compression load. The pattern of buckling wave formed in rhombic figure and the length of these wave in axial direction and circumferential direction were same. Buckling of thin cylindrical shell occured in the limit of elasticity and buckling load were less the theoretical balue. The results obtained were good agreement with the approximate solution and emperical formula for the buckling load be induced in the form
成洛元 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.2
A numerical model is developed to study the interactions of multiple angled jet flows in the inlet port plane of the two-stroke diesel engine cylinder. The random vortex method is used in two dimensions. Results show axisymmetric swirl initially. As flow develops, the centre of the swirl moves to the mid radius region and begins to precess about the cylinder centre. The flow becomes progressively more chaotic as time progresses.
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.
高溫疲勞에서 싸이클依存型 및 時間依存型 疲勞크랙傳播의 遷移 : 싸인應力波 및 사디리꼴應力波에 대하여
成洛元,周原植,韓根祚 東亞大學校 大學院 1984 大學院論文集 Vol.8 No.2
A study on the nonlinear fracture mechanics was made on the low-cycle fatigue crack growth in SUS304 stainless steel under trapezoidal and sine stress wave at 650℃. The high temperature low cycle fatique crack growth behavior was classified into two categories: cycle-dependent and time dependent. The cycle-dependent crack growth rate correlated well with J integral range ?J, whereas the time dependent crack growth rate was characterized by modified J integral Jex. A parameter βwas found useful in predicting the transition from the cycle-dependent crack growth to the time-dependent crack growth. Conducting the experiment of high temperature fatigue crack propagation in trapezoidal, and sine stress wave, following conclusions were obtained. 1. Crack propagation behavior can be classified into cycle-dependent and time-dependent. 2. The transition of cycle-dependent crack propagation to time dependent one could be predicted bt either parameter βor ?J/ ?J?.
成洛元,安贊祐,金賢洙 東亞大學校 大學院 1984 大學院論文集 Vol.8 No.2
This searched for conditions of the optimum absorber to eliminate the chatter vibration by the computer and its effects were confirmed experimentally. The results are as follows. 1. The amplitude ratio of workpiece according to mass ratio was obtained in the optimum absorber by computer. 2. The forced frequency ratio at maximum amplitude ratio according to mass ratio was obtained in the optimum absorber by computer. 3. By direct contact between workpiece and absorber the effects on the elimination of chatter vibration were confirmed.