• Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.103-110
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• 2016

This study shows the statistical properties of the domestic composite material prepregs test result. During the last three years(2012.5~2015.6) the prepreg specimen tests have been performed by referring to NCAMP developed test procedure which was approved by FAA. The database of (1) Carbon Tape, (2) Glass Fabric, and (3) Carbon Fabric composite material prepregs' characteristics have been established for certified aircraft structures. This qualified materials can be used for aircraft structural design through proper material equivalency procedures.

• Journal of Aerospace System Engineering
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• v.9 no.4
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• pp.43-48
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• 2015

This paper presents the systematic and procedural approaches to ensure the safety of the composite material domestically developed and produced, for its use in the structure of aeronautical product in accordance with the applicable international standard, and to enhance its creditability. Based on this approaches, this paper eventually proposes the practical future plan to encourage and expand the adoption of domestic composite material as part of aeronautical product by aircraft manufacturer in global market.

• East Asian Journal of Business Economics (EAJBE)
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• v.6 no.1
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• pp.31-41
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• 2018

Purpose - The main target to do this analysis is to find out the competitiveness between 2 countries (China and USA) in the aircraft business industry. The main target about mentioned research is to find out how a certain country takes more advantage against the other partner country in the country's trade structure. Research design, data, and methodology - Mentioned research period ranges from 1995 to 2016. Research basic data are coming from UN COMTRADE database which is top of top in the world statistical data and Research methods are used 3 types of international trade related theory for credible data outcomes. Results - Even though general data about aircraft industry are open to world society, detailed classified data are not easy to get them. Generally, Both China & USA are not easy to obtain data especially, in the overseas production field as a business secret which is one of research limitation in every research scopes. Conclusions - Even though Chinese aircraft industry looks like strong and more advantage against those of other countries based on competitive labor work wages and low price of raw material and resources, Actually, USA has overwhelmingly dominant advantage against that of China in the field of aircraft industry because USA has abundant capitals and up-to-date advanced high-technology as top of world economic communities. Additionally, even if USA aircraft industries hold a dominant position so far, if USA proposes sound competition relationship with China about aircraft industry, both 2 countries' future will be bright as their cooperation will make synergy effects for mutual benefits under current circumstances in 2 countries.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.504-509
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• 2004

Chemical machining(CHM) is a special process which material removed by contact of strong etchant. The application as industrial process was started from aircraft industry after 2nd world war. Chemical milling, one of the CHM process, initially became commercial bussiness and it was called chem-mill. Even today, this process widely used to remove the material from aircraft wings and fuselage panel in aircraft industry. In this study, it is attempted to design the cylinder pattern which minimize the weight within the allowable stress using chemical milling.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.6
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• pp.417-426
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• 2006

A Digital X-ray imaging system using Compton backscattering has been developed to obtain a cross-sectional profile and mass loss of corroded lap-splices of aging aircraft from density variation. A slit-type camera was designed to focus on a small scattering volume inside the material, from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the lap-joint is scanned by moving the scattering volume through the thickness direction of the specimen. The mass loss of each layer has been estimated from a Compton backscatter A-scan to obtain the thickness of each layer including the aluminum sheet, the corrosion layer and the sealant. Quantitative information such as location and width of planar corrosion in the lap splices of fuselages is obtained by deconvolution using a nonlinear least-square error minimization method(BFGS method): A simple reconstruction model is also introduced to overcome distortion of the Compton backscatter data due to attenuation effects attributed to beam hardening and quantum noise.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.573-583
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• 2017

This paper presents a first step towards the understanding of water diffusion in RTM textile composite materials for aircraft applications and focuses on the development of experimental and numerical approaches to characterize the diffusion kinetics within the material. The method consists in making samples which are representative of the materials architecture and carrying out gravimetric tests on such samples. Analysis of results with the aid of a diffusion model reconstructing the architecture of the samples helps identifying the diffusion behaviour of the material.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.5
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• pp.446-451
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• 2007

Since the introduction of advanced composite materials for use in aircraft, the material qualification has been a costly burden to the small airframe manufacturer. For each manufacturer, extensive qualification testing has often been performed to develop the base material properties and allowables at operating environmental conditions, regardless of whether this material system had been previously certificated by other manufacturers. In recent years, NASA, industry, and the FAA have worked together to develop a cost-effective method of qualifying composite material systems by the sharing of a central material qualification database. In this paper, the new methodology of composite material qualification is presented and material allowable of 350°F carbon fiber/epoxy composite material produced domestically is determined with this methodology.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.303-308
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• 2014

Aircraft are an indispensable mode of modern transportation. They are also used as in a wide variety of other fields. For example, aircraft are used for accommodating passengers, carrying freight, and for military reconnaissance. Aircraft ground operations include landing and taking off. During landing, a higher load is applied to the landing gear than during takeoff. The landing gear should absorb impact energy and prevent damage to the main body of the aircraft in the case of an accident. In this study, simulations were performed for two types of plate-spring-type landing gear: that made of composite materials and that constructed with aluminum. The structural safety of landing gear made of each material was also evaluated.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.84-91
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• 2011

A finite element analysis for the wing and landing gear of a composite target-drone air vehicle was performed. For the wing analysis, two load cases were considered: a 5g symmetric pull-up and a -1.5g symmetric push-over. For the landing gear analysis, a sinking velocity of 1.4 m/s at a 2g level landing condition was taken into account. MSC/NASTRAN and LS-DYNA were utilized for the static and dynamic analyses, respectively. Finite element results were verified by the static test of a prototype wing under a 6g symmetric pull-up condition. The test showed a 17% larger wing tip deflection than the finite element analysis. This difference is believed to come from the material and geometrical imperfections incurred during the manufacturing process.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.5
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• pp.681-691
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• 2008

Taking into consideration both the inconveniences reported with current working uniform for the aircraft mechanics and the subjects' requirements mentioned in preceded survey, the researchers designed an ergonomic sample garments with improved motional flexibility and comfort. To improve motional flexibility, extra folds were added to the back of the garments to allow for ease of motion of limbs, so that the material would not be drawn up by the motion of the arms. Darts were added to the elbow, hip, the knee. Furthermore, by increasing the length of the waist centerline, the hip region would not be drawn up. For improved comfort, $CoolMax^{(R)}$ was used as lining material for the armpit and back region to discharge swear promptly. Subjects and panels were asked to evaluate the sample garment that followed an ergonomic design and pattern. According to the results, the sample garment was evaluated more highly than the existing working uniform in appearance and motional flexibility. The field tests by three aircraft mechanics working in the Office of Forestry were also demonstrated that the sample garment was advanced in terms of motional flexibility and comfort.