• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.321-329
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• 1998

To ensure the structural integrity of the autofrettaged thick-walled cylinder subjected to cyclic internal pressure loading, the fatigue crack propagation life of the cylinder was evaluated. Stress intensity factors of the external cracked cylinder due to internal pressure and autofrettage loadings were calculated using the finite element method. The fatigue crack propagation lives of the cylinder based on the fracture mechanics concepts were predicted and compared to the experimental fatigue lives evaluated from the C-shaped simulation specimens. There were good correlations between the predicted and experimental fatigue lives within a factor of 3 for the single and double grooved C-shaped simulation specimens. Predicted fatigue crack propagation lives of the double grooved cylinders were about 1.5-5 times longer than those of the single grooved cylinders depending on the levels of autofrettage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.226-229
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• 2008

To investigate an in-pile behavior of the newly developed DUO fuel pellet, the irradiation test will be carried out in the domestic test reactor. Irradiation test capsule for the HANARO reactor, which is a specially designed equipment used for material, irradiation and creep test, must satisfy the operational requirement on the hydraulic characteristics and structural integrity. In this study, a pressure drop, a flow-induced vibration and a short-term endurance test for the newly developed non-instrumented test capsule were carried out using FIVPET as a out-pile evaluation test. The test results show that the new test rig satisfy the HANARO operational requirement with sufficient margin.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.100-103
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• 2002

The recent machine tools are requested so high-quality processing and productivity increasing. Therefore it is so necessary to develop technology far high-speed and high-precision. This thesis touches on the development of high speed and intellectual line center. At first, the line center is necessary that strong structure, compact structure and light weight design far high-speed processing and transfer. So. It is necessary that examination of new materials and structures for light-weight and control devices for precision processing. So. It is going to make mention of the process of 1st model production for the above-mentioned base on test model production and evaluation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1171-1174
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• 2005

Manufacturing capability at the micro or nano scale production field is requested strongly in view of parts and product miniaturization. Miniaturized parts and products will introduce lots of benefits in terms of high precision functionality and low energy consumption. This paper presents the results of micro milling machine tool development for micro machining process. Finite element analysis has been performed to know the relationship between design dimensional variables and structural stiffness in terms of static, dynamic, thermal aspects. Performance evaluation through machining has been tested and discussed for achievable machining characteristics.

• Proceedings of the KWS Conference
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• v.43
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• pp.67-69
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• 2004

The fuel assemblies as the nuclear fuel for the pressurized water reactor(PWR) are loaded in the reactor core throughout the residence time of three to five years. The spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the fuel assembly. The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral load acting on the fuel assembly so as to keep the fuel assembly straight. To meet the requirement, integrity on the spacer grid welding parts should be carefully checked. In this study, welding quality of the spacer grid assembly welded by several welding companies are examined and compared.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.457-464
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• 2010

Ever since the introduction of high strength steel pipe strut(POSTRUT) in 2008, there has been over 50 applications domestically. The merits of construction period reduction and cost savings have been well reported abroad in countries such as America, Europe and China but ever in domestic projects or ground condidtions. 25 actual construction projects were investigated and statistically analyzed to evaluate the quantitative effects of POSTRUT. Also the construction projects along with the cautions that should be taken and the structural behavior differences between POSTRUT and H-section struts are briefly described in this paper.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.646-657
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• 2010

Offshore wind power is one of the largest-scale solutions for a nuclear- and pollution-free electricity supply in the future. Recently, the research for offshore wind power has started in Korea. However, there has been little effort specifically made for the exploration and evaluation of mechanical characteristics for offshore underwater soil deposits. In offshore wind power system, this is important as consistent and safe maintenance of structural functionality of the system is key for the wind power system to be successfully implemented. In this study, case examples from foreign offshore wind power sites are selected and analyzed. And design methods and factors of offshore wind power system foundation are investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1448-1451
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• 2004

This study is concerned about the design and development of three dimensional bending machine. The purpose of this study is design and development of three-dimensional bending machine by analysis of bending process and structural analysis simulation. The analysis is carried out by FEM simulation using DEFORM and CATIA V5 software. Based on this study, the three dimensional bending machine was developed. In order to evaluate a performance and reliability of the developed three dimensional bending machine, we used laser interferometer and three axial measuring system.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.465-470
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• 2001

Three-sided concrete culverts can be used to replace short span bridges and multiple sections(barrels) of four-sided concrete box culverts. ASTM Standards do not specify designs for four-sided concrete box culverts with span lengths exceeding 3.6m(12ft) nor do they discuss the three-sided concrete culverts. This paper describes the analysis and design of three-sided flat-top Precast reinforced concrete culverts with span length or 4m(14ft). Both AASHTO and Korean specifications were used to compare the main reinforcing steel. It is shown that the related provisions of Korean specifications result in more conservative design than those of AASHTO specifications.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.953-958
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• 2002

The finishing method of concrete floor using automatic surface finisher is one of new technologies in concrete floor construction. The development of high technologies in construction will increase in order to satisfy the demand to construct high quality building. Using this method, it is possible to increase the quality of building as well as to reduce the labor work in site. In this paper, a system which can be used to finish the concrete floor using automatic surface finisher, is presented and its structural capacities are evaluated. The system is composed of rail which guides the surface vibrator and absorbs the volume change of concrete, and a device supporting the rail. From the experimental work for these devices, it was shown that the support and rail had suitable strength to resist the automatic surface finisher. For design purpose, also, effective span of supports was tabulated.