• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.12-21
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• 1997

Nowadays, non-pollution energy sources have been strongly needed because of the exhaustion of fossil fuels and serious environmental problems. Because wind energy can be enormously obtained from natural atmosphere, this type of energy has lots of advantages in a economic and pollution point of view. This study has established the aerodynamic and structural design procedure of the rotor blade with an appropriate aerodynamic performance and structural strength for the 500㎾ medium class wind turbine system. The aerodynamic configuration of the rotor blade was determined by considering the wind condition in the typical local operation region, and based on this configuration aerodynamic performance analysis was performed. The rotor blade has the shell-spar structure based on glass/epoxy composite material and is composed of shank including metal joint parts and blade. Structural design was done by the developed design program in this study and structural analysis, for instance stress analysis, mode analysis and fatigue life estimation, was performed by the finite element method. As a result, a medium scale wind turbine rotor blade with starting characteristics of 4m/s wind speed, rated power of 500㎾ at 12m/s wind speed and over 20 years fatigue life has been designed.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.534-541
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• 2010

With the financial sponsorship of FKI and six other companies, the design and construction of the human powered aircraft Sky Runner has been begun to design in December of 2008. And it flew in late December of 2009. The original design configuration was continuously modified in response to test results as a 30.36m span, $35.25m^2$ wing area, 26.0 aspect ratio and 39.8kg of empty weight. Although, we have made only 150m flight flying a few seconds so far however, it will contribute to the research of ultra-light and long duration flying planes. A brief review of some design features, wing layout, prop design, fabrication and flight test results are presented.

• Composites Research
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• v.29 no.2
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• pp.53-59
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• 2016

Aircraft wing structure is used as a fuel tank containing the fluid. Fuel tank and joint parts are consists of composite structure. Hydrodynamic Ram(HRAM) effect occurs when the high speed object pass through the aircraft wing or explosion and the high pressure are generated in the fuel tank by HRAM effect. High pressure can cause failure of the fuel tank and the joint parts as well as the aircraft wing structure. To ensure the aircraft survivability design, we shall examine the behavior of the joint parts in HRAM effect. In this study, static tensile tests were conducted on four kind of the composite T-Joints. The failure behavior of the composite T-joint was examined by strain gauges and high speed camera. We examine the validity of the Finite Element Modeling by comparing the results of FEA and static tensile tests. The failure stresses and failure pressure of the composite T-Joint were calculated by FEA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1028-1034
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• 2015

General composition and cholesterol contents of chicken 4 parts (breasts, thighs, legs without skin, and wings with skin) were analyzed. Fatty acids, amino acids, and mineral contents of breasts and thighs were also analyzed and compared with sirloin parts of beef and pork. Lipid contents of chicken parts (1.2% in breasts, 2.8% in thighs, and 14.9% in wings) were lower than those of beef and pork. Protein contents of chicken parts (22.9% in breasts, 19.7% in thighs, and 17.6% in wings) were higher than those of beef and pork. Cholesterol contents of chicken parts (99.0 mg% in wings, 80.8 mg% in thighs, and 56.7 mg% in breasts) were higher than those of beef and pork. However, saturated fatty acid contents of chicken (31.6~32.9%) was lower than those of beef (40.8%) and pork (42.7%). In the meanwhile, unsaturated fatty acid contents of chicken (67.1~68.4%) was higher than those of beef (59.2%) and pork (57.3%). Essential fatty acid contents of chicken (16.6~16.9%) were 1.6 times as high as that of pork (10.4%) and 5 times as high as that of beef (3.9%). Major amino acids composition were glutamic acid, aspartic acid, lysine, and leucine. Ten essential amino acid contents were 11,860 mg% in breasts and 10,454 mg% in thighs, and the ratio of essential amino acids (41.7~44.1%) was similar to those of pork and beef. Mineral contents of chicken were similar to those of pork and beef despites of slight different mineral contents in thighs and breasts.

• Journal of the Korea Institute of Military Science and Technology
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• v.1 no.1
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• pp.154-165
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• 1998

In this paper, the mongrel singular element with 6 node triangle and 8 node quadrilateral element with J-integral are developed and applied to the various plane crack problems for the isotropic material. The convergence nature is excellent for various crack size with even coarse mesh using the direct method. But the results of the mongrel element with J-integral are worse than the former's ones. Fracture tests were conducted on precracked CT specimens. Results show that, for 7075-T6 aluminum wing spar materials, the fracture toughness is 31.06 ksi.inch $\frac{1}{2}$ in the L-T direction.