• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.10
• /
• pp.928-935
• /
• 2015

This paper presents low temperature structural tests of a UAV wing which has room temperature-curing adhesive bond. The wing structure is made of carbon fiber reinforced composites, and the skins are bonded to the inner structures (such as ribs and spars) using room temperature-curing adhesive bond. Also, to verify damage tolerance design of the wing structure, barely visible impact damages are intentionally created in the critical areas. The attachment fittings of the wing are fixed in a specially designed chamber which can simulate the low temperature environments of the operating altitudes. The test load is applied by hydraulic actuators which are placed outside the chamber. The structural tests consist of strain survey tests and a durability test for 1-life fatigue load spectrum. During the tests, strains of major parts are measured by strain gauges and FBG sensors. The change of the initial impact damages is also monitored using piezoelectric sensors. The 1-life damage tolerance of the composite structure is verified by the structural tests under the simulated environments.

• 월간 기계설비
• /
• s.279
• /
• pp.48-53
• /
• 2013

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1999.10a
• /
• pp.20-20
• /
• 1999

고대로부터 이용되어온 풍력에너지는 특히 풍황이 양호한 서유럽을 중심으로 꾸준히 개발되어 왔다. 최근 세계 여러 나라에서는 화석에너지의 고갈과 심각한 환경오염 문제 등으로 인하여 청정에너지의 개발에 많은 투자를 하고있으며 이에 따라 우리 나라에서도 풍력발전기의 개발이 진행되고 있다. 풍력에너지의 효율적인 이용을 위해서 여러 가지 형태의 발전시스템이 시도되어 왔으나 최근에는 성능 및 효율성이 우수하고 일정 출력을 낼 수 있도록 깃 각 조정이 가능한 수평축 풍력발전시스템이 주로 사용되고 있으며 대형화함으로서 대두되는 경량화 문제를 해결하기 위해 복합재를 이용한 회전날개를 개발하여 이를 사용하고 있다.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.280-281
• /
• 2017

본 논문에서는 기존의 배풍기 효율을 높이고 크기를 줄이기 위해 임펠러의 속도를 높이는 설계에 관한 연구다. 임펠러 속도는 5500rpm으로 증가시키고 크기는 320mm에서 250mm로 줄였으며 효율과 최대 풍량을 향상키기기 위해 임펠러의 Hub/Tip 비율을 줄이며, 날개각도에 변화를 주는 방식을 제안한다. Hub/Tip 비율이 줄어들면 유량이 통과하는 면적이 넓어지게 되는 효과를 얻게 되고, 임펠러 중심거리에 따른 날개 각도를 변화시키면 풍압과 풍량이 달라지는 효과를 얻게 되어 동일한 rpm으로 회전하는 배풍기의 효율을 높일 수 있다. 설계된 구동용 SRM과 임펠러의 설계에 따른 운전 특성을 시뮬레이션을 통해 해석하고자 한다.

• The Korean Publising Journal, Monthly
• /
• s.173
• /
• pp.4-5
• /
• 1995

(주)서울출판유통과 (주)뿌리와날개가 합병한데 이어 치근에는 (주)한국출판유통이 공식 출범했고, 대형 도매상인 보문당과 청운이 합병을 준비하는 등 유통시장에 크나큰 지각변동을 예고한다. 출판관계자들은 이러한 유통업계 변하에 지지를 보내는 한편, 기존 상권과의 공존, 소매서점까지 관리가능한 전산체제의 구축 등 몇가지 문제를 제기하기도 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.8
• /
• pp.47-53
• /
• 2004

An Experimental investigation into the effects of the blowing jet type and jet orientation on the aerodynamic characteristics over an elliptic type airfoil is explored. This study is aimed at expanding the data base of blowing jet application in separation control of elliptic airfoil. Present data includes: surface pressure, blowing jet exit velocity measurements and integrated aerodynamic loads. The experiments were performed for an elliptic airfoil at Reynolds number $8.22{\times}10^5$. The improvement of effects of pulsed jet on the increase of aerodynamic characteristics was significant for the post-stall angle. For reduced mass flow rates, pulsed jet allowed considerably higher lift to be generated. The jet orientation also showed dominant parameter on the separation control Positive jet angle delay or avoid separation, whereas negative jet angle promotes it.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.3
• /
• pp.203-210
• /
• 2014

In this study, the hydrodynamic characteristics of Weis-Fogh type water turbine were calculated by the advanced vortex method. The wing (NACA0010 airfoil) and both channel walls were approximated by source and vortex panels, and free vortices are introduced away from the body surfaces. The distance from the trailing edge of the wing to the wing axis, the width of the water channel and the maximum opening angle were selected as the calculation parameters, the important design factors. The maximum efficiency and the power coefficient for one wing of this water turbine were 26% and 0.4 at velocity ratio U/V=2.0 respectively. The flow field of this water turbine is very complex because the wing moves unsteadily in the channel. However, using the advanced vortex method, it could be calculated accurately.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.1 no.1
• /
• pp.1-14
• /
• 2000

This paper is concerningon the development of cross-flow fan (CFF) for vehicles. CFF is widely usedhome-appliance products. This work mainly Intends developing CFF only for an automobile. In order to do that, new design involving blade shapes is proposed with enough performance for the operation. Spacially three steeps are proceeded for blade design. injection conditions for manufacturing, and capacity test for fluid mechanics. The present methodologies are to find optimal design for the blades and conditions for the injection process. This project has continued since last two years and finally succeeded.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.1
• /
• pp.50-55
• /
• 2011

In this study, simultaneous aero-structural design was performed for HALE aircraft wing. The span and the shape of main spar were considered as design variables. To maximize aerodynamic performance and to minimize weight, multi-objective optimization was used. Nonlinear static aeroelastic analysis was performed to compute large deflection of wing. Design of experiment and response surface method were used to reduce computation cost in the design process. Also, aerodynamic performances of deformed wing and rigid wing were compared.

• Journal of Aerospace System Engineering
• /
• v.9 no.2
• /
• pp.1-6
• /
• 2015

태양광 고고도 장기체공형 무인기나 인간동력 항공기 등에 사용되는 높은 종횡비를 가진 유연날개는 공력 및 구조 상호작용으로 인하여, 구조적 비선형 처짐 및 양력감소 등의 문제가 발생한다. 본 연구에서는 저속 비행하는 높은 종횡비를 가진 날개의 단방향 공력-구조 연계해석을 수행하였다. XFOIL을 사용하여 공력천이현상을 포함한 저 레이놀즈수 익형 공력특성 자료 확보를 기반으로 3차원 양력선 이론을 사용하여 공력해석 연구를 수행했다. 구조해석은 상용소프트웨어 ANSYS를 사용하여 구조변형이나 응력해석 연구를 수행했다. 단방향 공력-구조 연계해석 결과를 바탕으로 인간동력 항공기 주 날개의 형상설계 연구를 수행했다.