• 한국항공우주학회지
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• 제43권5호
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• pp.422-431
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• 2015

풍동실험에 적용하는 실험계획법을 연구하기 위한 선행 연구로써 KF-16의 정적 공력 데이터베이스를 구축하는 풍동 실험을 수행하였다. 본 실험에서 사용된 기체는 KF-16의 1/33 scale의 모델이며 수평 꼬리날개와 플래퍼론, 방향타를 모두 구현하였다. 크게 실험은 수평 꼬리날개의 유무에 따른 공력 특성 변화를 보기 위한 실험과 플랩, 플래퍼론, 방향타, 그리고 수평 꼬리날개의 변위각에 따른 공력특성 변화를 알아보기 위한 실험을 수행하였다. 실험 수행 후에는 각 실험들에 대해서 6가지 공력계수 그래프를 분석하고 반응 표면을 생성하면서 조종면의 변화가 각각 어떤 공력 특성에 큰 영향을 미치는지 알아보았다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.173-178
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• 2005

In this paper, an efficient and robust analysis system for the flutter optimization of laminated composite wings has been developed using the coupled computational method based on the genetic algorithm. General three-dimensional doublet-lattice method is efficiently used to compute generalized aerodynamic forces of T-tail configuration in the frequency domain. Structural dynamic analyses of laminated composite T-tail models are conducted using finite clement method. The classical P-k flutter analysis technique is applied to effectively solve the aeroelastic governing equations in the frequency domain. Optimum design studies using genetic algorithm have been conducted in order to obtain maximum flutter stability of a composite T-tail configuration. The results show that flutter stability can be significantly increased using composite materials with proper optimum design concepts even for the same weight and shape condition. In the view point of engineering design, it is also importantly shown that the optimization of the vertical wing part is highly effective comparing to the optimization of horizontal wing part.

• 한국항공우주학회지
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• 제45권3호
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• pp.173-179
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• 2017

본 논문에서는 모션캡쳐 카메라를 사용한 실험을 통해 날갯짓 비행체의 주 날개, 꼬리날개 구동기 특성 분석에 대하여 기술하였다. 실험은 빛이 차단된 실내에서 진행되었고 지그에 기체를 고정하여 날갯짓으로 인한 영향을 줄였다. 주 날개와 꼬리날개 끝단에 마커를 부착하였고 모션캡쳐 카메라는 입력 신호에 대한 각각의 반응을 측정한다. 실험 결과 주 날개는 날갯짓의 주파수에 따라 진폭이 변하는 경향을 보였고, Modified Strip Theory에 실험 결과와 비행체 제원을 적용하여 양력 및 추력 발생 시뮬레이션을 구현 하였다. 꼬리날개는 종 횡축별로 스텝 신호를 인가하여 이에 따른 결과를 2차 전달함수 형태로 정의하였고, 각 축별로 구동기의 구조 차이로 인하여 최종 응답시간, 오버슈트, 최대값 등에서 차이를 나타내는 것을 확인하였다.

• 대한기계학회논문집A
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• 제23권7호
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• pp.1196-1204
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• 1999

adaption of the model predictions is highly desirable. In general, the width deviation at the head and tail ends of strip may be different from that of the steady state region. Therefore, the dynamic edger corrections can be used to compensate the width deviations which would otherwise occur. For the precise width control, the effect of edger roll gap and rolling conditions on the width deviation of head and tail ends of strip has been investigated and the effective method to decrease width deviation has been proposed. On-line application of dynamic edger control method in this study shows about 50% width compensation at the head end of the strip, and near perfect compensation at the tail end of strip.

• Archives of Plastic Surgery
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• 제43권4호
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• pp.321-327
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• 2016

There are many women who want larger and brighter eyes that will give a favorable impression. Surgical methods that make the eye larger and brighter include double eyelidplasty, epicanthoplasty, as well as lateral canthoplasty. Double eyelidplasty produces changes in the vertical dimension of the eyes, whereas epicanthoplasty and lateral canthoplasty create changes in the horizontal dimension of the eyes. Epicanthoplasty, a surgical procedure which enlarges the eye horizontally, is performed at the inner corner of the eye, whereas lateral canthoplasty enlarges the outer edge of the eye. In particular, if the slant of the palpebral fissure is raised and the horizontal dimension of the palpebral fissure is short, adjusting the slant of the palpebral fissure through lateral canthoplasty can achieve an enlargement of eye width and smoother features. Depending on the patient's condition, even better results can be achieved if this procedure is performed in conjunction with other procedures, such as double eyelid-plasty, epicanthoplasty, eye roll formation surgery, fat graft, and facial bone contouring surgery. In this paper, the authors will introduce in detail their surgical method for a cosmetic lateral canthoplasty that lengthens the lateral canthal angle and corrects the outer tail of the eyes, in order to ease the unfavorable impression.

• 한국지진공학회논문집
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• 제19권6호
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• pp.293-302
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• 2015

ASCE 4 requires that a hard stop be built around the seismic isolation system in nuclear power plants. In order to maintain the function of the isolation system, this hard stop is required to have clearance-to-stop, which should be no less than the 90th-percentile displacements for 150% Design Basis Earthquake (DBE) shaking. Huang et al. calculated clearance-to-stop by using a Latin Hypercube Sampling technique, without considering the rocking behavior of the isolated structure. This paper investigates the effects on estimation of clearance-to-stop due to 1) rocking behavior of the isolated structure and 2) sampling technique for considering the uncertainties of isolation system. This paper explains the simplified analysis model to consider the rocking behavior of the isolated structure, and the input earthquakes recorded at Diablo Canyon in the western United States. In order to more accurately approximate the distribution tail of the horizontal displacement in the isolated structure, a modified Latin Hypercube Sampling technique is proposed, and then this technique was applied to consider the uncertainty of the isolation system. Through the use of this technique, it was found that rocking behavior has no significant effect on horizontal displacement (and thus clearance-to-stop) of the isolated structure, and the modified Latin Hypercube Sampling technique more accurately approximates the distribution tail of the horizontal displacement than the existing Latin Hypercube Sampling technique.

• 대한기계학회논문집B
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• 제30권10호
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• pp.1012-1018
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• 2006

To evaluate the aerodynamic efficiency of TR-S4 configuration, wind tunnel tests of 40% scaled model were done in KARI LSWT. TR-S4 configuration has different nacelle shape, larger EO/IR camera and aftward wing location compared with TR-S2. Component build-up test after adding each element of model is performed. Also effects of horizontal tail incidences, Flaperon and Aileron deflection. on aerodynamic characteristics are measured. Test results showed that TR-S4 configuration has favorable stability characteristics in longitudinal, lateral and directional for the pitch and yaw motions.

• 한국항공운항학회지
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• 제14권2호
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• pp.17-26
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• 2006

The flutter characteristics of all movable tail wing with honeycomb sandwich structure have been studied in this study. The present wing model has a airfoil cross section and the linear variation of spanwise thickness. Structural vibration analysis is performed based on the finite element method using sandwich and beam elements. Unsteady aerodynamic technique used on the doublet lattice method has been effectively used to conduct the frequency-domain flutter analyses. The parametric flutter studies have been performed for various structural design parameters. Computational results on flutter stability due to the variation of structural parameters are presented and its related characteristics are investigated through the comparison of results.

• 대한기계학회논문집B
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• 제28권7호
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• pp.800-808
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• 2004

Wind tunnel test of an airplane model with forward swept wing was done in KARI LSWT to evaluate and measure the aerodynamic characteristics of initially designed configuration. Since the given wing planform did not fully satisfy the design requirements, local flow control devices such as vortilon, vortex generator and flow fence were used to delay separation and to enhance aerodynamic characteristics. Also decision making processes of design parameters such as vertical tail boom length, the location, size and the incidence angle of horizontal tail were discussed. The general aerodynamic characteristics of forward swept wing for various control surface deflection conditions of flap, aileron and elevator were also given.

• 한국강구조학회 논문집
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• 제10권3호통권36호
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• pp.537-551
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• 1998

본 논문에서는 장기온도측정자료의 통계해석에 바탕을 두고, 합성박스형교량에 작용하는 설계온도하중의 적절한 값을 제안하고자 한다. 이를 위해, 최근에 건설된 합성박스형교량에서 약 20개월간 온도측정을 수행하였다. 극치해석에 앞서, 온도분포특성을 나타내는 주요 매개변수를 정의하고, 이의 계절별변화에 대해 상세히 검토하였다. 이 온도하중매개변수의 극치분포를 Tail-Equivalence법에 의해 결정하고, 주어진 재현기간에 해당되는 온도하중매개변수의 극치값을 계산하였다. 끝으로, 이 결과들을 현 시방서에서 온도하중에 대해 제안하고있는 규정들과 비교하였다. 비교결과로부터, 현 시방서는 합성박스형교량의 온도응력을 나타내는데 불충분하며, 특별한 경우에 있어서 현 설계규정에 포함되지않은 수평방향온도변화를 고려해야만 된다는 결론에 도달하였다.