• 대한조선학회논문집
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• 제47권5호
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• pp.697-702
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• 2010

A WIG(Wing-In-Ground effect) craft flies close to the water surface by utilizing a cushion of relatively high pressurized air between its wing and water surface. This implies that when one designs such craft it is important to have lightweight structures with adequate strength to resist external loads with some margins. To investigate this requirement, this paper deals with the structural analysis of the bottom plate of small WIG craft having a design landing weight of 1.2-ton. As building materials for the WIG craft, pre-preg carbon/epoxy composites are considered. The strength information of the bottom plate is obtained using the first-ply-failure analysis in conjunction with a mid-plane symmetric laminated plate theory. As a result, the first-ply-failure location, load and deflection of the bottom plate are obtained. The calculated strength information is compared with the water reaction load for the bottom plate of seaplanes considered when they land on the water surface -the same fluid-structure interaction mechanism as that of WIG craft. In the calculation of seaplane water reaction load information, the rules shown in FAR(Federal Aviation Regulations) Part 25 are used. Through the comparison, the structural integrity of the bottom plate for the WIG craft is checked.

• 대한구순구개열학회:학술대회논문집
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• 대한구순구개열학회 2002년도 종합학술대회
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• pp.27-27
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• 2002

• 한국항공운항학회지
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• 제14권1호
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• pp.22-27
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• 2006

The linear and nonlinear aeroelastic analyses of a flat plate wing with flaperon have been performed by using frequency-domain and time-domain analyses. Natural modes from free vibration analysis and a doublet-hybrid method (DHM) are used for the computation of subsonic unsteady aerodynamic forces. The flaperon hinge is represented by a free-play spring and is linearized by the described function method. The linear and nonlinear flutter analyses indicate that flapping mode of the flaperon, the hinge stiffness and free-play of hinge have significant effects on the aeroelastic characteristics. From the nonlinear flutter analysis, different modes like stable and unstable limit-cycle-oscillation are observed in same flutter velocity depending on initial conditions.

• 한국응용곤충학회지
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• 제56권4호
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• pp.435-436
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• 2017

곤충 머리에 있는 subgena (아랫뺨)와 clypeus (두순)는 연속된 피부판으로 통칭하여 peristome (입둘레판)으로 일컫는다. 따라서 subgenal sulcus (아랫뺨선)는 peristomal sulcus (입둘레홈) 또는 cranial-stomal sulcus (두개-입선)로 개정한다. 집파리류 성충 머리에 있는 ptilinal suture (이마주머니선)는 ptilinal fissure (얼굴주름)로 개정한다. 가슴에 있는 wing process (날개돌기)는 등판에 있는 것은 notal process (등판돌기), 옆판에 있는 것은 pleural process (옆판돌기)로 각각 개정한다. 곤충 몸 아래쪽을 지칭하는 영역을 복부는 ventum (배판), 가슴은 sternum (가슴판)으로 각각 지칭한다.

• 대한조선학회논문집
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• 제35권3호
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• pp.14-25
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• 1998

본 논문은 자유수면 위를 가까이 비행하는 표면효과익선(Wing-in Ground Effect Craft)의 날개에 작용하는 정상(steady) 및 비정상(unsteady) 동유체력을 포텐셜 기저 패널법을 사용하여 수치해석을 수행한 결과이다. 파가 없는 고정수면 위를 비행하는 정상문제의 경우에 대해서는 단면변화, 앙각(angle of attack), 가로-세로비(aspect ratio), 날개 끝단판(end-plate)의 부착 유무 및 비행고도에 따른 양력 및 항력을 계산하여 풍동실험 결과와 비교하였다. 비정상문제에서는 이미 정의된 파표면 위를 표면효과익이 날아가는 경계치 문제로 해석하였다. 파장, 파고, 비행고도의 변화에 따른 날개에 작용하는 비정상 동유체력을 계산하여 파가 있을 경우 표면효과의 영향을 살펴보았다.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.84-91
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• 2001

Comparison between performance of a plate fin and that of a modified plate fin is investigated as a function of the position, the non-dimensional width and height of wings as well as the non-dimensional fin length using a two-dimensional separation of variables method. The ratio of the incremental rate of heat loss to that of the area of a modified plate fin is also presented as a function of the height of wings. The modified plate fin is made by attaching the wings to upper and lower sides of a plate fin. One of the results shows that performance of a modified plate fin is more improved as the wings approach left (higher) thermal reservoir.

• International Journal of Aeronautical and Space Sciences
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• 제4권1호
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• pp.63-74
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• 2003

The vortical flow of a 65-deg flat plate delta wing with a leading edge extension(LEX) was examined through off-surface visualization, 5-hole probe and hot-film measurements. The off-surface flow visualization technique used micro water droplets generated by a home-style ultrasonic humidifier and a laser beam sheet. The angles of attack ranged from 10 to 30 degrees, and the sideslip angles ranged from 0 to -15 degrees. The Reynolds number was $1.82{\times}10^5$ for the flow visualization, and $1.76{\times}10^6$ for the 5-hole probe and hot-film measurements. The comparison of the visualization photos and the flow field measurement showed that the two results were in a good agreement for the relative position and the structure of the wing and LEX vortices, even though the flow Reynolds numbers of the two results were much different. The wing vortex and the LEX vortex coil each other while maintaining a comparable strength and identity at zero sideslip. Neither a looping of the wing vortex around the strake vortex, nor the lopsided coiling of the stronger strake and the weaker wing vortices was observed. At non-zero sideslip, the downward movement of the LEX vortex when going downstream was enhanced on the windward side, and the downward and inboard movement of the LEX vortex when going downstream was suppressed on the leeward side. The counterclockwise coiling of the wing and LEX vortices was decreased significantly on the leeward side.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.175-176
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• 2010

국내 도로교설계기준에서는 날개벽 길이가 8m 미만인 경우에 대해서 날개벽을 4개 구역으로 나누고 캔틸레버 구조로 간편하게 수계산하여 단면력을 산정하도록 하는 간편법을 제시하고 있다. 이러한 간편법은 수계산에 의존하던 때에 만들어진 규정으로 과도한 안전율을 고려하게 되어 경제성 면에서도 불리한 설계가 이루어지고 있다. 따라서 본 연구에서는 불합리한 교대 날개벽 관련 도로교설계기준을 개선하기 위해서, 날개벽을 2변 고정 판구조로 해석하고 시방서 단면력과 비교검토를 실시하여 현시방서의 문제점을 정량화하고 개선책을 제시하였다.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1511-1520
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• 2004

A flow visualization of the two-dimensional rigid fling-clap motions of the flat-plate wing are performed to gain knowledge of butterfly mechanisms that might be employed by butterflies during flight. In this numerical visualization, the time-dependent Navier-Stokes equations are solved for cyclic fling and clap types of wing motion. The separation vortex pair that is developed in the fling phase of the cyclic fling and clap motion is observed to be stronger than those of the fling followed by clap and pause motion(1st cycle motion). This stronger separation vortex pair in the fling phase is attributable to the separation vortex pair of the outside space developed in the clap phase as it moves into the opening in the following fling phase. Accordingly, higher lift and power expenditure coefficients in the fling after clap phase is caused by the stronger separation vortex pair.

• Computers and Concrete
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• 제23권5호
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• pp.361-376
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• 2019

In this research, bending analysis of a micro sandwich skew plate with isotropic core and piezoelectric composite face sheets reinforced by carbon nanotube on the elastic foundations are studied. The classical plate theory (CPT) are used to model micro sandwich skew plate and to apply size dependent effects based on modified strain gradient theory. Eshelby-Mori-Tanaka approach is considered for the effective mechanical properties of the nanocomposite face sheets. The governing equations of equilibrium are derived using minimum principle of total potential energy and then solved by extended Kantorovich method (EKM). The effects of width to thickness ratio and length to width of the sandwich plate, core-to-face sheet thickness ratio, the material length scale parameters, volume fraction of CNT, the angle of skew plate, different boundary conditions and types of cores on the deflection of micro sandwich skew plate are investigated. One of the most important results is the reduction of the deflection by increasing the angle of the micro sandwich skew plate and decreasing the deflection by decreasing the thickness of the structural core. The results of this research can be used in modern construction in the form of reinforced slabs or stiffened plates and also used in construction of bridges, the wing of airplane.