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신정우,박상욱,이무형,김태욱,Shin, Jeong Woo,Park, Sang Wook,Lee, Mu-Hyoung,Kim, Tae-Uk 한국항공운항학회 2014 한국항공운항학회지 Vol.22 No.2
There are several methods to improve the flight efficiency of HALE(High Altitude Long Endurance) UAV(Unmaned Aerial Vehicle). Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. In order to reduce the weight of airframe structures, new concepts which are different from traditional airframe structure design such as the mylar wing skin should be introduced. The spar is the most important component in a mylar skin wing structure, so the spar weight reduction is the key point for reduction of the wing structural weight. In this study, design trade-off study for the front spar of the HALE UAV wing is conducted in order to reduce the weight. Design and analysis procedure of high aspect ratio wing spar are introduced. Several front spar structures are designed and trade-off study regarding the weight and strength for the each spar are performed. Spar design configurations are verified by the static strength test. Finally, optimal front spar design is decided and applied to the HALE UAV wing design.
고고도 장기체공 태양광 무인기 EAV-3 기체구조 개발
신정우,박상욱,이상욱,김태욱,Shin, Jeong Woo,Park, Sang Wook,Lee, Sang Wook,Kim, Tae-Uk 한국항공운항학회 2017 한국항공운항학회지 Vol.25 No.3
Research for solar-powered high altitude long endurance(HALE) UAV was conducted by Korea Aerospace Research Institute(KARI), and the EAV-3 with 19.5m wing span was developed. For HALE flight, aircraft should be lightly designed. Especially, airframe structure that accounts for a large portion of the total weight of aircraft should be lightweight. In this paper, development process of airframe structure for solar-powered HALE UAV, EAV-3, is described briefly. Domestic developed T-800 grade CFRP(Carbon Fiber Reinforced Plastic) composite material with high modulus and strength was used to design main load carrying structures. Flightloads analysis that takes into account large structural deformation was carried out. Stress and flutter analyses for airframe structure sizing were conducted. Static strength test for main wing and aircraft ground vibration test were conducted successfully and structural integrity was secured.
신정우,김성찬,김성준,채동철,이상욱,김태욱,심재열,Shin, Jeong-Woo,Kim, Sung-Chan,Kim, Sung-Jun,Chae, Dong-Chul,Lee, Sang-Wook,Kim, Tae-Uk,Shim, Jae-Yeul 한국군사과학기술학회 2006 한국군사과학기술학회지 Vol.9 No.4
In this paper, full-scale airframe static test of 4-seater canard airplane(the Firefly) was explained. From the results of the structural analysis, 5 design limit loads test conditions and 11 design ultimate loads test conditions were selected. Test loads analysis was performed and test fixtures and load control system(LCS) were prepared to realize the test loads. To protect the test article during the test, the overload protection system was prepared. Strain and deflection values were acquired through the data acquisition system(DAS) to verify the structural analysis results.
멜트블로운 폴리프로필렌/실리카 에어로겔 부직포의 제조와 단열 특성 분석
신정우,정영규,Shin, Jung Woo,Jeong, Young Gyu 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.6
To develop heat insulation fabrics with lightweight, low volume and excellent thermal insulation properties, in this study, a binder-free polypropylene/silica aerogel nonwoven fabric with an area density of ${\sim}79.7g/m^2$ was fabricated via a facile melt-blowing process, and its structure, thermal conductivity and thermal insulation properties were investigated. For comparison, a polyester hollow fiber nonwoven having a similar area density of ${\sim}84.6g/m^2$ was prepared by needle-punching. Additionally, a series of composite nonwoven fabrics was prepared by layering the melt-blown polypropylene/silica aerogel nonwoven and the polyester hollow fiber nonwoven in various combinations, and their thermal insulation properties and thermal conductivity were analyzed. Scanning electron microscopic analyses revealed that 5 wt% silica aerogel added during the melt-blown process was adhered well to polypropylene fiber surfaces of the nonwoven fabric. As a result, the melt-blown polypropylene/silica aerogel nonwoven fabric exhibited a low thermal conductivity of $43mW/m{\cdot}K$ and relatively high level of thermal insulation performance, although its thickness (~1.5 mm) was lower than that (~2.2 mm) of needle-punched polyester hollow fiber nonwoven with a similar area density. The thermal conductivity was lowered and thermal insulation performance was improved, as the melt-blown polypropylene/silica aerogel nonwoven fabric was layered. It was also found that increasing the number of melt-blown polypropylene/silica aerogel nonwoven fabric layers in the composite nonwoven fabrics layered in various combinations decreased the thermal conductivity and improved the thermal insulating properties.
신정우(Jeong Woo Shin),김성찬(Sung Chan Kim) 한국복합재료학회 2002 Composites research Vol.15 No.4
면외전단하중(anti-plane shear loading)을 받는 기능경사 압전 세라믹 무한 스트립(functionally graded piezoelectric ceramic strip)의 상하 양쪽 끝단의 중앙에 평행하게 존재하는 유한한 크기의 균열(Griffith crack)에 대한 특이응력(singular stress)과 전기장(electric field)을 선형 압전 이론(theory of linear piezoelectricity)을 이용하여 결정한다. 푸리에 변환(Fourier transform)을 이용하여 복합적분 방정식을 구성하며, 이를 제2종 Fredholm 적분 방정식(Fredholm integral equation of the second kind)으로 표현한다. 또한 응력세기계수(stress intensity factor)와 에너지 해방률(energy release rate)에 대한 수치결과를 제시하였다. We consider the problem of determining the singular stresses and electric fields in a functionally graded piezoelectric ceramic strip containing a Griffith eccentric crack under anti-plane shear loading with the theory of linear piezoelectricity. Fourier transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. Numerical values on the stress intensity factor and the energy release rate are obtained.
Jeong Woo Shin(신정우),Young-Shin Lee(이영신),Sung Joon Kim(김성준) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.10
본 논문에서는 적분변환법을 이용하여 면외전단 충격하중이 작용하는 두 개의 서로 다른 압전재료층 사이의 기능경사압전재료 접합층 내부 균열에 대한 과도응답 해석 을 수행한다. 기능경사압전재료의 물성치는 두께 방향을 따라 연속적으로 변하는 것으로 가정한다. 라플라스 변환과 푸리에 변환을 이용하여 문제를 복합적분방정식으로 구성하고, 수치해석을 위해 복합적 분방정식을 제 2 종 프레드홀름 적분방정식으로 표현한다. 전기적 하중, 재료물성 치의 변화율, 각 접합층의 두께가 균열의 과도응답에 미치는 영향을 보기 위해 동에너지 해방률에 대한 수치해석 결과를 제시한다. Transient response of a crack in a functionally graded piezoelectric material (FGPM) interface layer between two dissimilar homogeneous piezoelectric layers under anti-plane shear is analyzed using integral transform approaches. The properties of the FGPM layer vary continuously along the thickness. Laplace and Fourier transforms are used to reduce the problem to two sets of dual integral equations, which are then expressed to the Fredholm integral equations of the second kind. Numerical values on the dynamic energy release rate (DERR) are presented for the FGPM to show the effects on electric loading, gradient of the material properties, and thickness of the layers. Computed results yield following conclusions: (a) the DERR increases with the increase of the gradient of the material properties of the FGPM layer; (b) certain direction and magnitude of the electric impact loading impedes crack extension; (c) increase of the thickness of the FGPM layer and the homogeneous piezoelectric layer which has larger material properties than those of the crack plane are beneficial to increase of the resistance of transient fracture of the FGPM layer.