• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.601-608
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• 2007

To meet demand of big capacity and high speed rotation for washing machine, more stress from bending and twisting are complexly loaded onto the shaft supporting the horizontal drum, causing problems in fracture strength and fatigue life. Shafting system is mainly divided into flange and shaft. Flange is located between the drum and shaft, transferring power from the shaft to drum, and acting as a supporter of the back of the drum. Because section of flange has various design factors according to configuration of flange, the optimum conditions can’t be easily determined. Using a design of experiment (DOE), this study was performed investigating the interaction effect between factors as well as the main effect of the each design factor under bending and twist and proposed optimum condition using center composition method among response surface derived from regression equation of simulation-based DOE.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.239-246
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• 2009

The Mode I interlaminar fracture toughness of woven fabric carbon/epoxy and glass/epoxy composites for a train carbody was measured and FEM analysis was conducted. The woven fabric epoxy composite manufactured by hand lay-up, has high stiffness and strength, good resistance for impact, fatigue, corrosion and in-plane failure. The DCB(Double Cantilever Beam) specimen made of woven fabric epoxy composite had the size of 180mm $\times$ 25mm $\times$ 5mm and the insert of 65mm. The Mode I interlaminar toughness of specimen was measured according to ASTM 5528-01. The crack propagation behavior of the DCB specimen was simulated using FEA with cohesive elements that model the adhesive layer between woven fabric plies.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.516-528
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• 2009

Form the application of long rail system the non-ballast steel plate bridges, fatigue strength increase and rail noise reduction can be expected. This is mainly form the reduction of the rail impact at the rail joint locations which already made to behave together from welds. In the high speed rail, application of long rail system is essential because without long rail system, the required serviceability level can not be achieved. But even with this long rail systems, the thermal expansion from the girder can not be absorbed in the normal bearing systems, and these expansion cause between girder and rail. Also unexpected rail buckling and fracture through rail thermal tension may happen. It was found through numerical analysis and field measurement that these problems can be avoided by semi-fixed bearing system. In this study, the benefits of non-ballast plate bridge through long rail system, especially at the point of girder stability, girder stiffness increase and bearing maintenance will be reviewed.

• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.1-4
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• 2011

The full spade rudder for the high speed has advantage to prevent gap cavitation of the rudder. DSME has developed the full spade rudder and GL has carried out CFD analysis and FE analysis to confirm strength and fatigue for DSME and Owner. Necessarily, it needs to compare rudder torque & rudder force between CFD, FE analysis and full scale measurement. This report introduces the measurement method and application of strain gauge for measuring the rudder torque and rudder force for the 8,400 TEU container ship.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.1085-1090
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• 2005

Rod-type fiber reinforced polymer plastics(FRPs) similar to reinforcing steel bars have rarely been considered. In this study, an experiment was performed using beams strengthened with rod-type CFRPs and high-strength mortar overlay. The test results show that the strengthened beams not only had improved endurance limits but also improved load carrying capacities, stiffness values, and cracking loads as compared to a non-strengthened beam. Strengthened beams anchored with bolts throughout their entire span had more efficient structural behaviors, including composite behavior on the interface between the concrete and mortar, and load carrying capacity, than a strengthened beam anchored only on the end block.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.32-38
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• 1999

Fatigue crack propagation behavior for block load in high strength aluminum alloys was investigated in this study. The materials used in this study are aluminum alloy 5052-H32. Initial crack was made by applying cyclic load to a through crack with chevron notch. Crack length was measured from calibration curve, which was plotted by known crack length and resistance of standard specimens. Load was obtained from linear regression formula. Unloading elastic compliance method was applied to check the crack closure and cracked area. The present study results can be usefully applied to predicting the change of crack propagation rate, the crack closure, and the delay of crack propagation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.644-650
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• 2007

Mechanical property evaluation of micrometer-sized structures is necessary to help design reliable microelectromechanical systems(MEMS) devices. Most material properties are known to exhibit dependence on specimen size and such properties of microscale structures are not well characterized. This paper describes techniques developed for tensile testing of thin film used in MEMS. Epi-polycrystalline silicon is currently the most widely used material, and its tensile strength has been measured as 1.52GPa. We have developed a tensile testing machine for testing microscale specimen using electro-magnetic actuator. The field magnet and the moving coil taken from an audio-speaker were utilized as the components of the actuator. Structure of specimen was designed and manufactured for easy handling and alignment. In addition to the static tensile tests, it is described that new techniques and procedures can be adopted for high cycle fatigue test of a thin film.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.76-82
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• 2002

The rapid-set cement concrete causes high hydration temperature and nay result in a high drying shrinkage and shrinkage-induced cracking. This problem may be fixed by incorporating polypropylene fibers in rapid-set cement concrete, because of increased toughness, resistance to impact, corrosion, fatigue, and durability. A series of concrete drving shrinkage tests was peformed in order to investigate the shrinkage properties of polypropylene fiber reinforced concrete with experimental variables such as concrete types, fiber reinforcement, W/C ratio, with and without restraint. Uni-axially restrained bar specimens were used for the restrained shrinkage tests. The results were as follows; The dry shrinkage of rapid-set cement concrete was much lessor than that oi OPC, probably because of smaller weight reduction rate by early hydration and strength development. The constraint and bridging effects caused by polypropylene fibers were great for the rapid-setting cement concrete when compared with that of plain concrete, and this resulted In increased resistance against tensile stress and cracking.

• Journal of Society of Preventive Korean Medicine
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• v.11 no.1
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• pp.109-129
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• 2007

This study aims at grasping the relativity between laborers' yangseng level and stress so as to present the groundwork for preventive oriental medicine approach in industrial health. The researcher prepared the questionnaire on general character, health-related yangseng level and chose 632 people to execute Autonomic balance test through heartbeat change. The collected material was analyzed by SPSS and tested by T-test, ANOVA. The general yangseng level average is 3.27, morality yangseng 3.91, sleep yangseng 3.39, mind yangseng 3.32, sex life yangseng 3.29, exercise yangseng 3.14, activities and rest yangseng 3.07, diet yangseng 2.95, seasonal yangseng 2.84. The highest is morality yangseng and seasonal yangseng is the lowest. In the aspect of yangseng level : Having a spouse, Non-smoking, Non-drinking, Regular exercising, Sufficient sleeping have higher yanseng levels. In Autonomic balance test, age from 35 to 40 has the highest autonomic activity and job period from 5 years to 10 years has the highest stress resistance. Non-smokers have high autonomic activity and stress resistance. Further, have low autonomic balance, stress index and fatigue strength. In the case of regular exercising person, he/she has high autonomic activity and stress resistance with low stress index. Regarding sleeping time, autonomic balance is the highest when he/she sleeps less than 6 hours. Stress resistance is the highest when he/she sleeps 7 hours and stress index is the highest when he/she sleeps 6 hours. After comparing the relativity between yangseng level autonomic balance test, only exercise yangseng has plus factor on autonomic activity and stress resistance and minus factor on stress ind ex and fatigue strength. Yangseng level has been affected by individual character and daily habits. Also stress is more influenced by daily habits than by individual character. We can find the relativity of exercise yangseng between yangseng and stress which suggests that we need to take measures to win over stress in individual health in the near future.

• Journal of Korean Medical Ki-Gong Academy
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• v.10 no.1
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• pp.100-129
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• 2007

This study aims at grasping the relativity between laborers' yangseng level and stress so as to present the groundwork for preventive oriental medicine approach in industrial health. The researcher prepared the questionnaire on general character, - health-related yangseng level and chose 632 people to execute Autonomic balance test through heartbeat change. The collected material was analyzed by SPSS and tested by T-test, ANOVA The general yangseng level average is 3.27, morality yangseng 3.91, sleep yangseng 3.39, mind yangseng 3.32, sex life yangseng 3.29, exercise yangseng 3.14, activities and rest yangseng 3.07, diet yangseng 2.95, seasonal yangseng 2.84. The highest is morality yangseng and seasonal yangseng is the lowest. In the aspect of yangseng level: Having a spouse, Non-smoking, Non-drinking, Regular exercising, Sufficient sleeping have higher yangseng levels. In Autonomic balance test, age from 35 to 40 has the highest autonomic activity and job period from 5 years to 10 years has the highest stress resistance. Non-smokers have high autonomic activity and stress resistance. Further, have low autonomic balance, stress index and fatigue strength. In the case of regular exercising person, he/she has high autonomic activity and stress resistance with low stress index. Regarding sleeping time, autonomic balance is the highest when he/she sleeps less than 6 hours. Stress resistance is the highest when he/she sleeps 7 hours and stress index is the highest when he/she sleeps 6 hours. After comparing the relativity between yangseng level autonomic balance test, only exercise yangseng has plus factor on autonomic activity and stress resistance and minus factor on stress index and fatigue strength. Yangseng level has been affected by individual character and daily habits. Also stress is more influenced by daily habits than by individual character. We can find the relativity of exercise yangseng between yangseng and stress which suggests that we need to take measures to win over stresses in individual health in the near future.