• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.355-365
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• 2006

The coupled time-integration method with a staggered algorithm based on computational structural dynamics (CSD), finite element method (FEM) and computational fluid dynamics (CFD) has been developed in order to demonstrate physical vibration phenomena due to dynamic aeroelastic excitations. Virtual flutter tests for the spanwise curved ing model have been effectively conducted using the present advanced computational method with high speed parallel processing technique. In addition, the present system can simultaneously give a recorded data file to generate virtual animation for the flutter safety test. The results for virtual flutter test are compared with the experimental data of wind tunnel test. It is shown from the results that the effect of spanwise curvature have a tendency to decrease the flutter dynamic pressure for the same flight condition.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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• pp.33-45
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• 2005

The 1/9-scale model of a fighter-type configuration was tested in the Micro-Craft 8ft ${\times}$ 12ft wind tunnel facility. An abrupt lift dump was found at a certain range of angle of attack under the pre-scheduled approach configuration. To avoid a probable unsatisfactory flight behavior due to the lift dump, various aerodynamic devices were suggested. Extensive tests applying the cutoff leading edge flaps, boundary layer fences, saw tooth and vortex generators were performed with flow visualization as well as force and moment measurements. Test results showed that the origin of the lift dump was caused by the secondary boundary layer flow separation generated from the strong interaction between wing and flap. Various solutions for avoiding the unfavorable feature were suggested with the merits and demerits.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.33-39
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• 2014

Feathering spindle is one of the critical parts of the rotor system in the Smart Unmanned Aerial Vehicle(SUAV) that it was manufactured with special material, Maraging C300. During the initial ground and tie-down flight tests of the SUAV, surface of the feathering spindle contacting to the needle-roller bearings showed excessive wear and dent due to high vibrating loads transferred from the rotating blades. Gas nitriding process was applied to the bearing contact surface of the feathering spindle to increase surface hardness so as to improve the surface defects. This paper briefly presents the gas nitriding process adopted and the spindle quality improvements including wear and corrosion resistance.

• The KSFM Journal of Fluid Machinery
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• v.15 no.5
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• pp.20-26
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• 2012

An APU(Auxiliary Power Unit) for helicopters has been developed in Korea and tested at the AETF(altitude engine test facility) in KARI(Korea Aerospace Research Institute) for the purpose of the military qualification. A cell correlation test was performed before the official test, and the results are within the tolerance. The APU has the capability of supplying electric power as well as compressed air to the helicopters. It was tested at bleed extraction conditions, electric power extraction conditions, and maximum continuous concurrent power conditions within the entire helicopter flight envelop. Some special test equipments were implemented for the measurement of air flowrate, electric power and so on. The tests were successfully performed and their results satisfy the requirements of the helicopters.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.7-12
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• 2011

The goal of fire prevention research is to eliminate fires as a cause of fatal accidents and there are two main areas of research. One is to prevent flame propagation during in-flight and it addresses fire hazards. The other is to minimize the possibility of flame penetration or fuselage burn-through and it aims toward post-crash survival include crash protection, emergency evacuation and post-evacuation survival. Civil aviation authorities world-wide are trying to identify threats and measure performance for fire prevention. The results of research are standardized and given as general directions of test methods. This paper has prepared to study and present the means of compliance to the fire prevention requirements and applicable test methods.

• Journal of Aerospace System Engineering
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• v.5 no.1
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• pp.13-16
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• 2011

All components such as structure, engine, electrical equipment, wire etc. should have certified qualities and functions for safe flight. The wire like a blood vessel of man is connected with most components and supply a electrical signal or power to them and only certified wire through a lot of tests such as rating, flame resistance, self-extinguishing, protection of EMI etc. must be used in aircraft. In other words, the wire should observe many certification requirements because it is one of the most important components.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.194-205
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• 2009

In geotechnical engineering, the mechanical characteristics of soil, the main material of geotechnical engineering, is highly related to the confining stress. Reduced-scale physical modeling is often conducted to evaluate the performance or to verify the behavior of the geotechnical systems. However, reduced-scale physical modeling cannot replicate the behavior of the full-scale prototype because the reduced-scale causes difference of self weight stress level. Geotechnical centrifuges are commonly used for physical model tests to compensate the model for the stress level. Physical modeling techniques using centrifuge are widely adopted in most of geotechnical engineering fields these days due to its various advantages. In this paper, fundamentals of geotechnical centrifuge modeling and its application area are explained. State-of-the-art geotechnical centrifuge equipment is also described as an example of KOCED geotechnical centrifuge facility at KAIST.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.46-51
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• 2001

A mechanism of hovering flight of small insects which is called the Weis-Fogh mechanism is applied to ship propulsion. A model of the propulsion mechanism is based on a two-dimensional model of the Weis-Fogh mechanism and consists of one or two wings in a square channel. A model ship equipped with this propulsion mechanism was made, and working tests were performed in a sea. The model ship sailed very smoothly and the moving speed of the wing was small compared with the advancing speed of the ship.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.573-576
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• 2004

KARI is achieving the KSLV program according to National Space Technology Development Program. In this paper, the authors are intended to introduce the Integrated Power Plant (abb. IPP) test facility which will be constructed for the variety of tests on KSLV program. IPP test facility refers to comprehensive testing equipment for liquid rocket launch vehicle. Using this facility, KARl can verify the adaptiveness of parts and subsystems for launch vehicle and finally can qualify the system characteristics of launch vehicle doing kinds of test including hot firing test. Using this facility, KARI can simulate the vehicle launching circumstances and it make to predict the performance of launch vehicle when its flight test.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1078-1082
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• 2017

This paper presents an L1 optimization based filtering technique which effectively eliminates the optical misalignment effects encountered in the squint guidance mode with strapdown seekers. We formulated a series of L1 optimization problems in order to separate the bias and the gradient components from the measured data, and solved them via the alternating direction method of multipliers (ADMM) and sparse matrix decomposition techniques. The proposed technique was able to rapidly detect arbitrary discontinuities and gradient changes from the measured signals, and was shown to effectively cancel the undesirable effects coming from the seeker misalignment angles. The technique was implemented on embedded flight computers and the real-time operational performance was verified via the hardware-in-the-loop simulation (HILS) tests in parallel with the automatic target recognition algorithms and the intra-red synthetic target images.