• Aerospace Engineering and Technology
• /
• v.4 no.1
• /
• pp.1-8
• /
• 2005

Civil aviation regulation such as FAR and loads analysis procedure based on this was explained, and loads analysis procedure and results for Smart UAV was presented for application case. For loads analysis, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of 4-seater canard airplane was performed with ARGON and that results were presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.7
• /
• pp.76-84
• /
• 2005

For flight loads analysis of Smart UAV, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is a multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of Smart UAV which is a FAR 23 category airplane was performed with ARGON and the results were presented.

• Phonetics and Speech Sciences
• /
• v.7 no.1
• /
• pp.21-26
• /
• 2015

The aim of this study is to synthesize pathological breathy voice and to make a cepstral peak prominence (CPP) table following breathiness ranks by cepstral analysis to supplement reliability of the perceptual auditory judgment task. KlattGrid synthesizer included in Praat was used. Synthesis parameters consist of two groups, i.e., constants and variables. Constant parameters are pitch, amplitude, flutter, open phase, oral formant and bandwidth. Variable parameters are breathiness (BR), aspiration amplitude (AH), and spectral tilt (TL). Five hundred sixty samples of synthetic breathy vowel /a/ for male were created. Three raters participated in ranking of the breathiness. 217 were proved to be inadequate samples from perceptual judgment and cepstral analysis. Finally, 343 samples were selected. These CPP values and other related parameters from cepstral analysis are classified under four breathiness ranks (B0~B3). The mean and standard deviation of CPP is $16.10{\pm}1.15$ dB(B0), $13.68{\pm}1.34$ dB(B1), $10.97{\pm}1.41$ dB(B2), and $3.03{\pm}4.07$ dB(B3). The value of CPP decreases toward the severe group of breathiness because there is a lot of noise and a small quantity of harmonics.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.10
• /
• pp.1057-1064
• /
• 2008

In this paper, static and oscillatory instability of nanopipes conveying fluid and modelled as a thin-walled beam is investigated. Effects of boundary conditions and non-classical transverse shear and rotary inertia are incorporated in this study. The governing equations and the three different boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for different boundary conditions of carbon nanopipes are investigated and pertinent conclusion is outlined.

• Proceedings of the KOSOMBE Conference
• /
• v.1991 no.05
• /
• pp.94-97
• /
• 1991

It is well known that multipoint and computerized intraoperative mapping systems improve the results of surgery for Wolff-Parkinson-White syndrome and show tremendous potential for opening an entirely new era of surgical intervention for the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, the ability to map and ablate the sometimes fleeting automatic atrial tachycardia is greatly enhanced by computerized mapping systems. In this study, we have developed 16 channel computerized data analysis system using microcomputer for basic research of electrophysiology and electrical propagation. This system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the results of diagnosis and surgical treatment for cardiac arrhythmia.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.295-300
• /
• 2005

The freeplay, one of the concentrated structural nonlinearities, is inevitable for control surfaces of a real air vehicle due to normal wear of components and manufacturing mismatches. Also aerodynamic nonlinearities caused by a shock wave occur in transonic region. In practice, these nonlinearities induce the limit cycle oscillation (LCO) and decrease the transonic flutter speed. In this study, the fictitious mass method is used to apply a modal approach to nonlinear structural models due to freeplay. The transonic small-disturbance (TSD) equation is used to calculate unsteady aerodynamic forces in transonic region. Nonlinear aeroelastic time responses are predicted by the coupled time integration method (CTIM). This method was also applied to a 3D all-movable control wing to investigate its nonlinear aeroelastic responses. The angle of attack effect on the LCO characteristics has been found to be closely related with the initial pitching moment.

• 한국방재학회:학술대회논문집
• /
• 2007.02a
• /
• pp.445-448
• /
• 2007

교량의 플러터 발생풍속을 예측할 경우에는 주로 주형의 2차원 단면실험을 통하여 추정하고, 전체교량의 3차원 모형실험을 통하여 확인하게 된다. 주형단면의 2차원 단면모형 실험에서는 교량거더의 수직방향과 비틀림 방향의 2자유도계로 간략화하여 구조물의 거동을 살펴보게 된다. 전산풍공학적 방법에 의하여 구조물의 공기력을 산정하는 방법은 기존에 주로 사용되던 풍동실험을 대치하는 방법으로 개발되고 있으며, 교량의 플리터 발생풍속 예측을 위한 산정기법 역시 다양하다. 본 논문에서는 유사한 형상비를 가지는 $\pi$형 단면 거더의 플러터 발생풍속을 비교하였으며, 교량단면의 2차원 단면실험을 통하여 그 결과값을 비교, 검토하였다.

• International Journal of Aeronautical and Space Sciences
• /
• v.12 no.2
• /
• pp.179-189
• /
• 2011

In this paper, robust adaptive control design problem is addressed for a class of parametrically uncertain aeroelastic systems. A full-state robust adaptive controller was designed to suppress aeroelastic vibrations of a nonlinear wing section. The design used leading and trailing edge control actuations. The full state feedback (FSFB) control yielded a global uniformly ultimately bounded result for two-axis vibration suppression. The pitching and plunging displacements were measurable; however, the pitching and plunging rates were not measurable. Thus, a high gain observer was used to modify the FSFB control design to become an output feedback (OFB) design while the stability analysis for the OFB control law was presented. Simulation results demonstrate the efficacy of the multi-input multi-output control toward suppressing aeroelastic vibrations and limit cycle oscillations occurring in pre- and post-flutter velocity regimes.

• Journal of Mechanical Science and Technology
• /
• v.18 no.4
• /
• pp.560-572
• /
• 2004

Aeroelastic response and control of airfoil-flap system exposed to sonic-boom, blast and gust loads in an incompressible subsonic flowfield are addressed. Analytical analysis and pertinent numerical simulations of the aeroelastic response of 3-DOF airfoil featuring plunging-pitching-flapping coupled motion subjected to gust and explosive pressures in terms of important characteristic parameters specifying configuration envelope are presented. The comparisons of uncontrolled aeroelastic response with controlled one of the wing obtained by feedback control methodology are supplied, which is implemented through the flap torque to suppress the flutter instability and enhance the subcritical aeroelastic response to time-dependent excitations.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.7
• /
• pp.699-709
• /
• 2009

In this paper, the nonlinear dynamics and the stability of nanopipes conveying fluid and modelled as a thin-walled beam is investigated. Effects of boundary conditions, geometric nonlinearity, non-classical transverse shear and rotary inertia are incorporated in this study. The governing equations and the three different boundary conditions are derived through Hamilton's principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Variations of critical flow velocity for different boundary conditions of carbon nanopipes are investigated and compared with linear case.