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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Aeronautical & Space Sciences
Journal Basic Information
Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 37, Issue 12 - Dec 2009
Volume 37, Issue 11 - Nov 2009
Volume 37, Issue 10 - Oct 2009
Volume 37, Issue 9 - Sep 2009
Volume 37, Issue 8 - Aug 2009
Volume 37, Issue 7 - Jul 2009
Volume 37, Issue 6 - Jun 2009
Volume 37, Issue 5 - May 2009
Volume 37, Issue 4 - Apr 2009
Volume 37, Issue 3 - Mar 2009
Volume 37, Issue 2 - Feb 2009
Volume 37, Issue 1 - Jan 2009
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Numerical Investigation on Interference Effects of Tandem Rotor in Forward Flight
Lee, Jae-Won ; Oh, Se-Jong ; Yee, Kwan-Jung ; Kim, Deog-Kwan ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 615~626
DOI : 10.5139/JKSAS.2009.37.7.615
The objective of this study is to investigate the interference effects due to tandem rotor's overlap in the forward flight. To resolve the instabilities caused by close proximity of the wake to the blade surface, the field velocity approach is implemented to the existing unsteady panel code coupled with a time-marching free wake model. The modified code is then used to investigate the effects of the selected parameters on the forward flight performance of the tandem rotor. The calculated results for rotor separation effect indicate that stagger(d/D) appears to have little effects on the forward flight performance at high advance ratio and the square of gap(H/D) is inversely proportional to overlap induced power factor. In addition, it is also shown that the overlap induced power factor increases to a certain extent and decrease back as the advance ratio increases.
A Study on the Optimization of Ply Angles for Composite Tube using Design of Experiments
Park, Byong-Ug ; Seo, Yu-Deok ; Kim, Hyun-Jung ; Youn, Sung-Kie ; Lee, Seung-Hoon ; Lee, Deog-Gyu ; Lee, Eung-Shik ; Chang, Su-Young ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 627~633
DOI : 10.5139/JKSAS.2009.37.7.627
Composite has become one of the most frequently used material for a tube of satellite camera due to its attractive characteristics. However, laminated composites can be weakened by delamination which comes from interlaminar stress. Such failure mode cause structural instability of the camera as well as degradation of optical quality. Therefore composite tube should be robust in delamination. Also, composite tube should have high stiffness, sufficient high natural frequency and small coefficient of thermal expansion. The design procedures presented in this paper are based on design of experiments. The experiments for mechanical analysis are designed by the tables of orthogonal arrays. In order to manipulate the various mechanical properties systematically, multiple-attribute decision making(MADM) is employed. Through analysis of variance and F-test, the critical design variables which have dominant influences on mechanical performance are determined. Finally improved ply angles for composite tube are determined.
Vibratory Hub Loads of Helicopters due to Uncertainty of Composite Blade Properties
You, Young-Hyun ; Jung, Sung-Nam ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 634~641
DOI : 10.5139/JKSAS.2009.37.7.634
In this work, the behavior of vibratory hub loads induced due to the uncertainties of composite material properties for each of the participating rotor blades is investigated. The random material properties of composites available from the existing experimental data are processed by using the Monte-Carlo simulation technique to obtain the stochastic distribution of sectional stiffnesses of composite blades. The coefficients of variation (standard deviation divided by the mean) obtained from the sectional stiffness constants are used as an input to the comprehensive aeroelastic analysis code that can evaluate the hub loads of a rotor system. It is found that the uncertainty effects of composite material properties inevitably bring a dissimilarity to the rotor system. The influence of hub vibration response with respect to the individual stiffness (flatwise bending, chordwise bending and torsion) changes is also identified.
Prediction of Fretting Fatigue Life for Lap Joint Structures of Aircraft
Kwon, Jung-Ho ; Joo, Seon-Yeong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 642~652
DOI : 10.5139/JKSAS.2009.37.7.642
Most of lap jointed aircraft structures encounter the fretting damages, which provoke fretting cracks prematurely and lead to significant reduction of fatigue life. In the case of ageing aircrafts especially, this fretting fatigue problem is a fatal threat for the safety and airworthiness. Recently, as the service life extension program(SLEP) of ageing aircrafts has become a hot issue, the prediction of fretting fatigue life is also indispensable. On these backgrounds, a series of experimental tests of fretting fatigue on bolted lap joint specimens, were performed. And the fretting crack initiation and propagation life of each specimen were evaluated using existing and newly proposed prediction models with the fretting parameters obtained from the FEA results for elasto-plastic contact stress analyses. The validations of prediction models were also discussed, comparing the prediction results with experimental test ones.
A Study on the prediction of braking time for rotor brake system considering the friction coefficient variation with temperature
Choi, Jang-Hun ; Oh, Min-Hwan ; Cho, Jin-Yeon ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 653~660
DOI : 10.5139/JKSAS.2009.37.7.653
A helicopter rotor brake system stops or reduces the speed of the rotor by transforming the kinetic energy into the heat energy. The frictionally generated heat has a considerable effect on the frictional property of material itself and causes the change of the friction coefficient which may affect the breaking time significantly. In this paper, to take into account the effect of change of friction coefficient according to temperature on braking time, thermo-mechanically coupled analysis is carried out by commercial software ABAQUS. Further, simple theoretical equation is derived considering thermo-mechanical behaviors. The predicted braking times both from theoretical and numerical methods are compared and validity of proposed theoretical equation is investigated.
Estimation of Slosh Model Parameters Using Experimental Test-bed
Oh, Choong-Seok ; Sun, Byung-Chan ; Park, Yong-Kyu ; Roh, Woong-Rae ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 661~668
DOI : 10.5139/JKSAS.2009.37.7.661
The slosh natural frequencies, damping ratio, slosh mass and slosh force applying point of the liquid in cylindrical tank are estimated using the nonlinear least squares method in time domain. The estimated slosh model parameters are in good agreement with the results of the theoretical calculations for various liquid depths. Furthermore, this methodology will be applied to predict the sloshing parameters for a liquid propellant tank using ground experimental test-bed.
Roll/Yaw Momentum Management Method of Pitch Momentum Biased Spacecraft
Rhee, Seung-Wu ; Ko, Hyun-Chul ; Jang, Woo-Young ; Son, Jun-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 669~677
DOI : 10.5139/JKSAS.2009.37.7.669
In general, the pitch momentum biased system that induces inherently nutational motion in roll/yaw plane, has been adapted for geosynchronous communications satellites. This paper discusses the method of roll attitude control using yaw axis momentum management method for a low earth orbit(LEO) satellite which is a pitch momentum biased system equipped with only two reaction wheels. The robustness of wheel momentum management method with PI-controller is investigated comparing with wheel torque control method. The transfer function of roll/yaw axis momentum management system that is useful for attitude controller design is derived. The disturbance effect of roll/yaw axis momentum management system for attitude control is investigated to identify design parameters such as magnitude of momentum bias and to get the insight for controller design. As an example, the PID controller design result of momentum management system for roll/yaw axis control is provided and the simulation results are presented to provide further physical insight into the momentum management system.
Integer ambiguity propagation method for a precise positioning using GNSS carrier phase measurements
Han, Deok-Hee ; Yun, Hee-Hak ; Park, Chan-Sik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 678~684
DOI : 10.5139/JKSAS.2009.37.7.678
Many researches on the GNSS integer ambiguity resolution methods for precise positioning and attitude determination applications have been done. However, by the time invariant property of the integer ambiguity, the reuse of integer ambiguity without performing time consuming integer search procedure is possible. In this paper, a new efficient integer ambiguity propagation method is proposed. The initial integer ambiguity can be determined using the famous LAMBDA method and it is propagated with the propagation method. The proposed method can reconfigure the integer ambiguity using the previous epoch's integer ambiguity and new carrier phase measurements under environmental variations such as geometry changes, signal blockage and reacquisition. Experiments with real measurements show the proposed method can determine an integer ambiguity effectively.
The Development of the Rotorcraft Multidisciplinary Design Optimization Framework and Conceptual Design Using the KHP-SDM RMDO
Choi, Won ; Hwang, Yu-Sang ; Kim, Cheol-Ho ; Kim, Sang-Hun ; Lee, Dong-Ho ; Park, Chan-Woo ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 685~692
DOI : 10.5139/JKSAS.2009.37.7.685
This paper dealt with the development of the Framework for Multidisciplinary Design Optimization for the rotorcraft design concept and the building process of KHP(Korea Helicopter Project) - SDM(Simulation Data Management) system to manage various analysis data, which are used in the rotorcraft development phase. KHP-SDM RMDO(Rotorcraft Multidisciplinary Design Optimization) framework, which applied optimization modules of KHP-SDM and integrated the developed Multidisciplinary analysis modules, was constructed in the KHP-SDM. The results of the rotorcraft conceptual design using KHP-SDM RMDO showed that the framework was evaluated to be successfully constructed.
Impact Resistance of Composite Laminates Manufactured by New z-Pinning Technique
Choi, Ik-Hyeon ; Ahn, Seok-Min ; Yeom, Chan-Hong ; Hwang, In-Hee ; Lee, Dae-Sung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 693~700
DOI : 10.5139/JKSAS.2009.37.7.693
In this paper, conventional z-pinning technology which can be used to reinforce inter-laminar property of laminated composites is introduced and new z-pinning technique recently proposed by author is also introduced. On some trial specimens manufactured by the new z-pinning technique, the low-velocity impact test was performed and impact damage area was measured. Similar impact test was performed on normal composite laminate specimens and those test results were compared to each other. Consequently, it can be seen that the new z-pinning technique is more useful in applying to mass production of z-pinned composite laminate structures than the conventional techniques and some clear improvement on impact resistance of z-pinned composite laminates manufactured by the new z-pinning technique is observed.
Verification of Flight Control Law Similarity and HILS Environment Reliability for Fighter Aircraft
Ahn, Seong-Jun ; Kim, Chong-Sup ; Cho, In-Je ; Lee, Eun-Yong ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 701~708
DOI : 10.5139/JKSAS.2009.37.7.701
The flight control law of developed flight control computer(DFLCC) is developed based on operation flight program of advanced trainer aircraft full scale development final configuration. The flight control law design is used common use development tool in GUI(Graphic User Interface) environment. The flight control law transformed to C-Code is reflected in OFP. The OFP is verified by the standardized verification process. But, before standardized verification process, we need preliminary verification process such as similarity of flight control law and reliability of developed HILS. Similarity of flight control law is verified by comparing the aircraft response of advanced trainer aircraft and those of the developed control law. Also, reliability of developed HILS is verified by comparing the aircraft response of HILS and Non-real time simulation result. This paper verifies similarity of developed control law and reliability of HILS environment as comparing aircraft response.
An Investigation in the Thermal Effect on a Low Earth Orbit Satellite under Yaw Motion for the Visibility of a Star Sensor
Kim, Hui-Kyung ; Lee, Jang-Joon ; Hyun, Bum-Seok ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 709~716
DOI : 10.5139/JKSAS.2009.37.7.709
Thermal condition according to the operation attitude of a satellite in orbit would be essential to be known because the orbit attitude is a dominant factor to affect satellite thermal design. In this paper, the change in space thermal environment and the thermal effect in thermal design are studied for a low earth orbit satellite according to the yaw motion. The present satellite retains sun-pointing attitude during daylight due to the fixed type solar arrays. And it also moves along the orbit with constant yaw motion in a longitudinal axis so that a star tracker which is a star sensor for satellite's attitude control always looks into the deep space. This attitude is considered in its better visibility to the stars for a successful mission operation. Also, it is required to access the corresponding thermal effects due to the yaw motion. Therefore, we try to verify these by the thermal analysis for the satellite thermal model with the yaw motion.
The Past and Future Perspectives of Hydrogen Peroxide as Rocket Propellants
Ha, Seong-Up ; Kwon, Min-Chan ; Seo, Kyoun-Su ; Han, Sang-Yeop ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 37, issue 7, 2009, Pages 717~728
DOI : 10.5139/JKSAS.2009.37.7.717
In the field of rocket propulsion system hydrogen peroxide has been used as mono-propellant and as the oxidizer of bi-propellants. At the beginning, hydrogen peroxide was used as mono-propellant for thrusters, but later it had been replaced by hydrazine, which has better specific impulse and storability. On the other hand, to drive turbo-pumps, hydrogen peroxide is still being utilized. As the oxidizer of bi-propellants it was used until 1970's and from 1990's hydrogen peroxide once again got back to developer's interest, because one of the recent development purposes of rocket propulsion system is low-cost and ecologically-clean. Until now the storability of hydrogen peroxide has been remarkably improved. The combination of Kerosene/
also shows similar accelerating performance to Kerosene/
combination because of higher propellant density and higher O/F ratio, even though the propulsion performance is not as good as the combination of Kerosene/
. Moreover, its combustion products are much cleaner than Kerosene/