• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.311-318
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• 2000

In constructions of dams and ports structure, gravels are used as principle structural materials. Gravels have different material property compared with other materials like soil and concretes, etc. For example, material properties of gravels obtained from normal triaxial compression test are usually overestimated due to scale and penetration effects. Also, material properties of gravels under dynamic loads are the main interest when structural behavior of rockfill dam under earthquake loads is analyzed. The development of large triaxial compression apparatus is needed for the better estimation of material property of gravel. This paper reports work in progress to development of large triaxial compression apparatus.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.117-119
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• 2003

When material properties depend much on positions in a material or it is difficult to make test specimens from a material or component, an instrumented indentation test described in ISO 14577-1, 14577-2 or KS B 0950 can be used to measure material properties and damage. In this study, first of all, the principals of the instrumented indentation test, KS B 0950 are introduced and yield strengths, tensile strengths and work hardening exponents of base materials, heat affected zones and weld materials are measured. In addition, the influence of post-weld heat treatment on the material properties are investigated.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.67-70
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• 2000

This study was performed to investigate the material behavior of hybrid thermoplastic composites contained glass fiber and calcium carbonate. The composite was prepared with each combination ratio of calcium carbonate, and the content of glass fiber was fixed with 10% by weight. In order to investigate the material behavior for various combination ratio, tension test, flexural test, and impact test were performed. Microscopic observation were conducted to examine the fractured surface of specimen for tension test. And the material behavior of the hybrid thermoplastic composite immersed in salt water with definite time was investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.352-359
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• 2005

In this study, seismic refraction survey and MASW at dam crest and down-hole test and cross hole test in the boring holes located in dam crest through the core are performed to fin out dynamic material properties, are needed to evaluate dynamic safety of rockfill dam using dynamic analysis method. From the field test and geophysical exploration, applied such as above, p-wave and s-wave velocity profile of each layer of dam body. Dynamic material properties, such as elastic modulus, shear modulus, poissong's ration, are obtained from p-wave and s-wave velocity profile and density profile from formation density logging test.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.193-198
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• 2000

The small punch test have been developed to evaluate the material strength of the power plant components. This small punch test specimen is very small than the conventional strength test specimens. Korea Electric Power Research Institute (KEPRI) have been applying this test to assess accurately the life of thermal power plant and enhancing the reliability. The small punch test for gas turbine blades is under development. It's possible to compare the relative strength among the same materials having different operation histories. In this paper, the strength reductions of gas turbine materials are investigated by the small punch tests. All materials shows the almost same strength and deformation with the allowable deviation. At the same test temperature, the damaged material has the maximum load value. The strength reduction is not shown in this small punch test results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.429-432
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• 2009

The deformation and burst pressure of composite motor case highly depends on fiber material properties. Therefore, measuring exact fiber material properties is a priority item to develop a advanced composite motor case. However, the fiber material properties in composite motor case is very sensitive on the various processing variables (equipment, operator and environmental condition etc..)and size effect, so the fiber material properties can't be measured exactly from the existing specimen test method. This paper suggests a newly developed test method, hoop ring test, that is capable of pressure testing with ring specimens extracted from real composite motor case. The results of hoop ring test showed excellent agreement with measured fiber material properties from hydro-burst test with full scale composite motor cases.

• Journal of Drive and Control
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• v.19 no.3
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• pp.32-38
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• 2022

The in-wheel drive gearbox for military special vehicles converts the high-speed & low-torque output generated by the electric servomotor, into low-speed & high-torque mechanical power. As the vehicle is remotely maneuvered in mountainous terrain, wet fields, rough terrain, etc., the gearbox must generate a maximum input speed exceeding 5,000 rpm, a maximum torque of 245 Nm, and MTBF of 9,600 km. The purpose of this study was to analyze the failure mode of the gearbox, to ensure the durability of the in-wheel drive gearbox. Also, the field load test data of the vehicle was analyzed, the acceleration durability test standards were established, the acceleration durability test was conducted, and the durability test results were analyzed as well.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.487-490
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• 2005

In this study, for the establishment of the performance evaluation methods and the quality control standards of durability recovery method, the data of indoor durability test and the data of the long term exposure test under the coast are accumulated and analyzed. As a result of the indoor test, durability of repair material was more superior to that of plain concrete, but as a result of investigating and evaluating exposure test at 30 month of exposure age under the coastal environment, the difference in electric potential and the reinforcement corrosion at place replaced with repair material are found.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.807-810
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• 2005

In this study, MMA-modified paste of coating material for protecting the concrete structures was developed. The coating material was applied to cement concrete specimens by brush, roller and spray in each of which one, two and three layers to survey, by the cold-hot iterative test, the neutralization test, the chloride ion permeation test and the ante-abrasion test, the affect of painting methods and layers influencing on the durability of coating material. Results of the cold-hot iterative test showed that, regardless of the painting methods and layers, the defects such as crack or fuzz on surface were not produced. As the number of painting layers increased, the neutralization prevention as well as the chloride ion permeation prevention effects were increased. On the other hand, no difference was found between the painting methods. Reducing weight by abrasion of polymer paste coating material was $20\%$ comparing to that of cement mortar.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.52-59
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• 2016

Environmental Qualification has been almost developed except those of Non-Material Sub-components for valves and pumps though the time has only passed about 10years since EQ test launch of Korea. However EQ test has been performed by a few of engineers under the conditions that experience of EQ test is insufficient and EQ system is not developed completely. In recent years, Strengthen Nuclear Safety Regulation is being done Strictly Nuclear safety components Verification Procedure for Non-Material Sub-components, but the reports contain only performance test results, not Enviro nmental test methods relating to real Aging Degradation. In this Study, there were developed to performance systematically research to acquire EQ technology for five specimens of the Non-Material Sub-components in the Nuclear Power Plant.