• 한국항공운항학회지
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• 제27권4호
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• pp.1-8
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• 2019

Recently, development of long endurance electric powered airplane has been conducted worldwidely. Light structural weight of a main wing with sufficient structural integrity is essential for long endurance flight. Since a main wing with a slender spar can occur catastrophic fracture under the flight, it is important to establish a design and verification method for both the weight reduction and structural integrity. In this paper, structural design and analysis of the main wing of HALE UAV with tubular spar reinforced with a bulkhead were introduced. The static strength test of the main wing was performed to verify structural integrity under the static load. Then, the experimental result was compared with an analytical result from a finite element analysis. It was concluded that the developed light weight main wing would have sufficient structural integrity under the flight operation.

• 한국정밀공학회지
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• 제21권12호
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• pp.21-28
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• 2004

In modem manufacturing industries such as the airplane and automobile, aluminum alloys which are remarkable in durability have been utilized effectively. High-speed machining technology for surface roughness quality of workpiece has been applied in these fields. Higher cutting speed and feedrates lead to a reduction of machining time and increase of surface quality. Furthermore, the reduction of time required for polishing or lapping of machined surfaces improves the production rate. Traditional milling process for high speed cutting can be machined with end mill tool. However, such processes are generally cost-expensive and have low material removal rate. Thus, in this paper, face milling cutter which gives high MRR has developed face milling cutter body for the high speed machining of light alloy to overcome the problems. Also vibration experiment to detect natural frequency in free state and frequency characteristics during machining are performed to escape resonance.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.209-217
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• 2016

Unlike conventional airplane, a WIG craft experiences righting moment and adverse yaw moment in banked turning in ground effect. Numerical simulations are carried out to study the aerodynamics of banked wing in ground effect. Configurations of rectangular wing and delta wing are considered, and performance of endplates and ailerons during banking are also studied. The study shows that righting moment increase nonlinearly with heeling angle, and endplates enhance the righting. The asymmetric aerodynamic distribution along span of wing with heeling angle introduces adverse yaw moment. Heeling in ground effect with small ground clearance increases the vertical aerodynamic force and makes WIG craft climb. Deflections of ailerons introduce lift decrease and a light pitching motion. Delta wing shows advantage in banked turning for smaller righting moment and adverse yaw moment during banking.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2015년도 추계학술대회
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• pp.35-38
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• 2015

본 연구에서는 스포츠급 경항공기 모형의 공력 특성을 공군사관학교 아음속 풍동에서 측정하였다. 풍동시험은 유속 40m/s에서 이전 모델과 최근 공력성능 향상을 위해 보완된 모델에 대해 비교 실험 수행하였으며, 정확한 데이터를 얻기 위하여 흐름각 효과, 벽면효과, 지지대 간섭효과를 보정하여 공력계수를 산출하였다. 실험 결과, 두 모델의 항력계수와 양력계수가 전체적으로 유사한 경향성을 보이나 고받음각에서의 양력특성의 차이가 발생하였다. 또한 실제 비행 시의 레이놀즈 수 유동을 모사하기 위하여 Trip strip의 영향에 대하여 실험하였다. 그 결과 Trip strip을 부착하였을 경우 항력계수가 증가하고 최소항력받음각이 낮아지는 결과를 획득하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2008년도 추계학술발표대회
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• pp.656-657
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• 2008

Light Detection and Ranging (LiDAR) data has been used to detect the objects of earth surface from huge point clouds gotten from the laser scanning system equipped on airplane. According to the precision of 3~5 points per square meter, objects like buildings, cars and roads can be easily described and constructed. Many various areas, such as hydrological modeling and urban planning adopt this kind of significant data. Researchers have been engaging in finding accurate road networks from LiDAR data recent years. In this paper, A novel algorithm with regard to extracting road points from LiDAR data has been developed based on the continuity and structural characteristics of road networks.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.11-18
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• 1999

Recently advanced countries are now beginning to use ACM (Advanced Composites Material), which is mostly used in the industry of airplane, ship building and sports equipments, in the construction industry. Compared with existing construction materials, ACM possesses many advantages such as light-weight, high-strength, corrosion resistant property. Among other manufacturing process of ACM, pultrusion is one of the promising one of civil engineering application. In this paper, the structural characteristics of pultruded GFRP strip were studied. Major parameters to influence structural behavior of pultruded GFRP are considered to be fiber volume fraction, die temperature, pulling speed and fiber orientations. The effect of these parameters are studied by experimently and analytically. From this study, it is concluded that fiber volume fraction and fiber orientations influence more on the mechanical property of pultruded GFRP. In addition to above parametric study, off-axis tests were carried out and the results are compared with failure theories. It showed that they agree well each other. Since this study is carried out in limited scope, further research on the reinforcement in the transverse direction, experiment on the compressive strength and research on the durability should be conducted for wide application of pultruded GFRP sections.

• 산업경영시스템학회지
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• 제46권4호
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• pp.160-172
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• 2023

In contemporary global warfare, the significance and imperative of air transportation have been steadily growing. The Republic of Korea Air Force currently operates only light and medium-sized military cargo planes, but does not have a heavy one. The current air transportation capability is limited to meet various present and future air transport needs due to lack of performance such as payload, range, cruise speed and altitude. The problem of population cliffs and lack of airplane parking space must also be addressed. These problems can be solved through the introduction of heavy cargo planes. Until now, most studies on the need of heavy cargo plane and increasing air transport capability have focused on the necessity. Some of them suggested specific quantity and model but have not provided scientific evidence. In this study, the appropriate ratio of heavy cargo plane suitable for the Korea's national power was calculated using principal component analysis and cluster analysis. In addition, an optimization model was established to maximize air transport capability considering realistic constraints. Finally we analyze the results of optimization model and compare two alternatives for force structure.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.94-102
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• 2015

Optical camera communication (OCC) is an extension of Visible Light Communication. Different from traditional visible light communication, optical camera communications is an almost no additional cost technology by taking the advantage of build-in camera in devices. It was became a candidate for communication protocol for IoT. Camera module can be easy attached to IoT device, because it is small and flexible. Furthermore almost smartphone equip one or two camera for both back and font side with high quality and resolution. It can be utilized for receiving the data from LED or positioning. Actually, OCC combines illumination and communication. It can supply communication for special areas or environment where do not allow Radio frequency such as hospital, airplane etc. There are many concept and experiment be proposed. In this paper we proposed utilizing Android smart-phone camera for receiver and introduce new approach in modulation scheme for LED at transmitter. It also show how Manchester coding can be used encode bits while at the same time being successfully decoded by Android smart-phone camera. We introduce new data frame format for easy decoded and can be achieve high bit rate. This format can be easy to adapt to performance limit of Android operator or embedded system.

• 공업화학
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• 제27권3호
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• pp.252-258
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• 2016

중량의 감소 및 향상된 기계적 특성은 항공 우주 산업으로의 적용을 위한 재료의 새로운 소재를 개발하기 위해 주요한 인자이다. 복합소재는 가벼운 무게와 탁월한 물성으로 항공기와 타 교통수단용 소재로써 주목을 받아왔다. 특히 섬유강화 복합소재의 경우 금속을 대신할 소재로 사용되어 왔는데 이는 금속과 고분자 소재보다 우수한 물성을 나타내기 때문이다. 이러한 이유로 복합소재는 비행기의 구조물로 사용되어 왔다. 본 리뷰에서는 항공기에 적용된 복합소재의 장점과 섬유강화 플라스틱 복합소재 소재에 대하여 정리하였다.

• 수산해양기술연구
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• 제40권4호
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• pp.351-359
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• 2004

본 연구에서는 실선에 적용된 알루미늄 하니콤 샌드위치 판 (AHSP)을 저자가 제안한 심재의 형상이 피라미드인 알루미늄 샌드위치 판의 구조적 특성 및 진동특성을 검토해 보았다. 알루미늄 피라미드 샌드위치 판(APSP)의 기초 자료로 쓰일 수 있게 심재의 각도변화, 높이변화 및 면재와 심재의 두께변화에 따른 구조적 특성을 검토한 결과 APSP가 강도 및 강성에서 우수함을 보였으며, 질량대비 큰 강성 때문에 고유진동수도 다소 크게 평가되었다.