• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.87-94
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• 2023

This paper addresses the installation and modification design of airframe structures for new and modified equipment installations that are essential for aircraft performance improvement. Typical performance improvement equipment mounted on the exterior of the aircraft include antenna, radar, electro-optical/infrared (EO/IR), and self-protection system equipment, which require structural reinforcement, modification, and mounting design of the green aircraft for operation. In the interior of the aircraft, console and rack structures are modified or added according to user operation requirements. In addition, this is accompanied by the installation design of equipment to be replaced and added for performance improvement, and the according modification of environmental control system components for internal cooling. The engineering process and cases in which airworthiness was verified through the detailed design of airframe structures with structural integrity, operability, and maintainability of performance-improved aircraft are presented.

• Aerospace Industry
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• v.81
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• pp.12-17
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• 2003

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.5
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• pp.482-489
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• 2010

This paper describes the test procedure, instrumentation, verification methodology and the results of the ground vibration test(GVT) and force vibration test(FVT) of the SmartUAV aircraft to estimate experimentally dynamic characteristics of the aircraft. Bungee cords are used to emulate free-free boundary conditions of the test aircraft. The SmartUAV is excited by three shakers and one-hundred frequency response functions(FRF's) is measured. The FRF's are reduced and analyzed to identify the dynamics parameters of the SmartUAV. To extract modal parameters of the SmartUAV such as, natural frequencies and damping ratios, the poly-reference least square complex exponential method is used in the time domain. The mode shape coefficients are estimated with the least squares frequency domain method to identify the vibration modes. The FVT was performed by fixed sine frequency with three shakers on the x, y and z direction and vibration characteristics of structures and detail equipments are measured.

• Aerospace Industry
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• v.50
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• pp.23-27
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• 1997

쌍발복합재 항공기가 지는 3월 29일 마침내 땅을 박차고 올랐다. 지난 93년부터 개발이 시작된 쌍발복합재 항공기는 국내최초로 전 기체구조물을 복합재로 제작되었으며 개발과정에서 많은 시행착오와 시련을 겪기도 하였으나 마침내 처녀비행에 성공한 것이다. 본 고에서는 그동안의 개발과정과 의의를 개발실무자로부터 들어보기로 한다.

• Defense and Technology
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• no.9 s.139
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• pp.40-53
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• 1990

세계시장에서 멜버른의 기록은 매우 인상적이다. 이곳 회사들은 국내외 보잉 747 창정비시설과 정비시설등을 공급하였고, 록히드사엔 항공기 격납고를, GE사엔 F404, T700 엔진을, NEC사엔 인공위성 부품을, 프랑스의 에이버스 항공사엔 기체구조물(Floor support structure), MD사엔 MDX헬기의 기체를, 보잉사엔 복합재료를 사용한 Rudder시스템을 공급하였다. 생산품의 3분의 1 이상은 해외수출을 하며, 이외의 많은 생산품과 부품은 미국, 유럽, 아시아지역등에 판매하고 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.376-381
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• 2010

The structural strength tests are usually performed to evaluate the structural strength and to verify the structural design and analysis of the vehicle structures. In this paper, the development of a compressed loading type apparatus to load distributed force over the surface of vehicle structure subjected to external loads was described. This apparatus is for structural materials which are easily to fail because of concentrated stresses. This apparatus can apply loads to specimens without any damage on the test specimen's surfaces by using flexible membrane and can be applicable to several kinds of surface profile of structures. The structural strength tests for the flat structure and curved structure with this apparatus were successfully performed, and the test results showed that this type of loading apparatus can be adequate to verify the structural integrity of the fragile structures.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.78-85
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• 2022

Multicopter-type unmanned aerial vehicles (UAV) are increasingly for cargo transportation to mountainous and island regions, image information acquisition in disaster areas, and emergency rescue transport. In order to successfully perform these tasks, the aircraft structure must be able to safely support the loads induced by flight conditions while ensuring the vibration and aeroelastic stability of the prop-rotor. This study introduced a structural analysis model of a 40kg payload multicopter with an engine-generator hybrid power system. The deformation and stress distribution are investigated depending on the load conditions. In addition, the vibration characteristics and aeroelastic stability of the prop-rotor were also presented to flight speed and aircraft pitch angle. The maximum thrust generated by the prop-rotor and the landing load applied to the multicopter under normal and emergency landing conditions were reviewed., It confirmed that the structure could support without failure. In addition, it confirmed that the damping characteristics of each primary locate in the constant region according to the aircraft's flight speed and the prop-rotors rotating speed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.44-51
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• 2017

An ultra light quad-rotor is utilized in various areas for military and commercial purpose. Especially, the airframe shape is designed with various airframe size, weight and purpose. In this paper, the initial airframe shape of the quad-rotor was designed and manufactured. Flight test was conducted for the quad-rotor. The design modification of airframe shape was conducted to meet design requirement. By changing design, weight of airframe structure was reduced and payloads were placed to the best position. By reinforcing ribs and reducing vehicle's legs, the durability of airframe structure was enhanced.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.94-103
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• 2018

The purpose of designing composite lattice structure which applied to launching vehicle and tactical missile body is to minimize the thickness and weight for applied load. It is usually made of carbon fiber; fabricating with filament winding process over silicon mold, and provided with a window opening for inspection purpose if necessary. In this paper compression test is conducted without window opening in lattice structure and preliminary FEA is carried out to confirm its accuracy. And then FEA is performed for the case of window opening to evaluate the soundness and the safety factor of the structure. We have calculated for two kinds of window shape; rectangular one and hexagonal one. And we have calculated safety factors of the lattice structure with window opening in every case based on failure strength of rib and knot with varying the thickness and location of the window for hexagonal shape. Through our investigation, we have found out the followings; (1) the hexagonal shaped window is shown higher safety factor than rectangular one, (2) a window in a certain location is shown higher safety factor than others, (3) although the soundness of window structure is improved as increasing its thickness, a window of a certain thickness is shown higher safety factor than others because of stress concentration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.385-386
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• 2010