70계열 알루미늄합금 용접부의 피로균열진전 거동과 피로수명 예측에 관한 연구

옹장우,김재훈,정근춘 忠南大學校 産業技術硏究所 1988 산업기술연구논문집 Vol.3 No.1

It has been important to determine life cycle and stress range for the each welded metal under high cycle load control test conditions. In this study, fatigue crack propagation rate for 7017, 7020, 7039 and 5083 alluminum welded alloy was compared with stress intensity factor range linear elastic fracture mechanics. Compact tension specimens were used and crack growth rate da/dN and stress intensity factor range ΔK were analyzed concerning to the R value of 0.1 and 0.3. In order to find out the value of ΔK, ΔK-inceasing test method was applied by the standard fatigue testing method describes in ASTM E647-81. From the result, the stable crack propagation region of 7017, 7020, 7039 and 5083 alluminum welded alloy was applicable to the Paris equation da/dN = C(ΔK)m (C and m are material constants). Constant m decreases and constant C increases with increasing of stress ratio R. Without dependence on materials, the fatigue life and the propagation rate increase, while the gradients of crack propagation rate decrease, whith increasing stress ratio. Fatigue life was observed roughly in the order of 7020 > 5083 > 7017 > 7039, independently on crack propagation direction and stress ratio. The fatigue life is longer when the crack propagation direction of specimen and welded bead are parallel to each other than transverse. The crack propagation rate and the gradient of it are larger in the case of parallel specimen than transverse. The minimum crack length of fatigue life can be estimated through the knowledge of maximum equivalent crack length obtained by using nondestructive test.

圓孤齒形 齒車의 물림機構가 Pumping에 미치는 影響

邕章祐 충남대학교 공업기술개발연구소 1975 工業技術開發硏究所論文集 Vol.2 No.2

This study was theorized about the gearing mechanism of pump gears which have circular arc tooth profile. The results obtained are as follows. 1. In all of gearing positions, the minimum clearance of backlash was stood on the tooth trace. 2. When gears were in motion, the position of maximum cleanae of back-lash was positioned periodically on 1/4 or 2/1 of diametral pitch. 3. In the case of about 0.02mm allowable tolerance on gear tooth profile, the leakage of gearing could be prevented by the effectual selection of R and r. 4. Extreme wear position was located on the line of pitch surface. 5. It was unfit tooth profile for the height speed pump.

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.

전자빔용접 AL5083-H113재의 불안정 피로균열 진전속도 예측에 관한 연구

옹장우,오재협 충남대학교 공업교육연구소 1989 論文集 Vol.12 No.1

Fatigue crack growth rate of electron beam weldments of AL5083-H113 are compared with basemetal under high cycle-load control test condition. The Kaiser's expression for the crack growth rate's prediction is modified to predict the instabe fatigu crack growth rate. The modified Kaiser's expression is evaluated under low cycle-load control test conditions and the effect of load condition is studied.

알루미늄材의 彈塑性破壞靭性評價에 關한 硏究

邕章祐,金載勳,朴昞俊 충남대학교 공업교육연구소 1986 論文集 Vol.8 No.3

It has been very important to evaluate the J_IC in Elastic-Plastic Fracture toughness test and to develope the certain method that we can precisely obtain the J_IC from any material. In this study, R-curve Method, Stretch Zone Method, and Ultrasonic Method are used to evaluate the J_IC of Aluminums, i.e., Al 2024, Al 5083, Al 7075. The echo energy of Ultrasonic Method increased rapidly in the unstable crack growth stage and then it is decreased at less rapidly slope. Therefore, the value of J_IC exists between linearly decreased region and the point of deviation. J_IC can be obtained precisely by Stretch Zone Method and approximately obtained by Ultrasonic Method. Stretch Zone Method can be used to evaluate J_IC very quantitively, but we have the trouble with the method in measurement. Ultrasonic method is required that the research for the more exact evaluation about correlation between echo energy and the crack openning behavior of precrack tip will be continued.

Graphite/Epoxy 적층복합판의 저속충격에 의한 손상거동

옹장우,김재훈,전제춘 忠南大學校 産業技術硏究所 1995 산업기술연구논문집 Vol.10 No.2

Damage behavior of quasi-isotropic circular composite plates of Herculus AS4/3501-6 graphite/epoxy were investigated and the residual compressive strength after impact under low-velocity impact type loads was evaluated. The locations and lengths of damages inside the plate after the impact were calculated by means of a three-dimensional finite element method and compared with the impact test results. Also, the load-deflection curves for impact were used to predict the major damage characteristics of the impact force in the laminated composites.

回轉 Separator Ring 갖인 Rotary Pump에 關한 考察

邕章祐 충남대학교 공업기술개발연구소 1976 工業技術開發硏究所論文集 Vol.3 No.2

In eccentric rotary pump there are many complicated mechanisms because the length of separator is changed periodically in eccentric center. These studies were the performances upon the idea of the rotary pump with a rotating separator ring. The results were as follows: 1. The length of separator is constant. 2. Discharge is constant on outline. 3. Outside and inside pump chamber ratio is determined by the rotor diameter. 4. Driving-shaft must be rotor-shaft. 5. The mechanisms are, comparatively simple.

材料試驗의 效果的인 指導를 위한 敎授學習敎材의 開發

邕章祐,柳盛淵,姜理錫 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)

Instructional materials were developed for effective teaching of materials testing and to promote the maximum use of the newly acquired experimental equipments. We have developed experimental manual and slide films. These materials comprise of tension test, compression test, bending test, hardness test, impact test, fatigue test, wear test and magnetic particle inspection. This study will contribute to teaching and laboratory practice of materials testing.

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℃.

얇은 圓板의 비틂좌굴에 關한 實驗的 硏究

邕章祐,李永臣 충남대학교 1977 工業技術開發硏究所論文集 Vol.4 No.1

The thin circular plates are widely used as the parts of machines and instruments. Problems of torsion of a circular plate are not widely studied. The modern use of circular plates as the machineparts has made the static and dynamic stability of a circular plate a problem of great importance. In this study, relation between torsional critical stress S and ratio of radii from 1.5 to 4 was found by experiment. In this range, the results give valuable data for the practical coupling design. This results are good agreement with Dean's theoretical value.