• Smart Structures and Systems
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• v.1 no.2
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• pp.159-184
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• 2005

The paper intends to summarize some guidelines for future smart structure system application in military aircraft. This preview of system integration is based upon a review on approximately one and a half decades of application oriented aerospace related smart structures research. Achievements in the area of structural health monitoring, adaptive shape, adaptive load bearing devices and active vibration control have been reached, potentials have been identified, several feasibility studies have been performed and some smart technologies have been already implemented. However the realization of anticipated visions and previously initial timescales announced have been rather too optimistic. The current development shall be based on a more realistic basis including more emphasis on fundamental aircraft strength, stiffness, static and dynamic load and stability requirements of aircraft and interdisciplinary integration requirements and improvements of integrated actors, actuator systems and control systems including micro controllers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.36-41
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• 2014

Electro-Mechanical Actuator installed on aircraft consists of a decelerator which magnifies the torque to rotate an axis connected with aircraft control surface, a control section which controls the motor assembly through receiving orders from cockpit and a motor assembly which rotates the decelerator. EMA controls aircraft attitued, position, landing, takeoff, etc. It is important part of a aircraft. Aircraft maneuvering make vibration of EMA. Vibration may cause the vibration fatigue. For that reason, it is necessary to analyze the system safety. In this paper, first EMA is modeled in finite element method and analyzed the response from input vibration. second EMA is tested and analyzed from modal experimental data. third EMA Fe model is updated and re analyzed. and EMA is verified safety with $3{\sigma}$ stress and S/N curves.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.5 s.110
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• pp.503-513
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• 2006

The duration time of aircraft noise event is also an important factor for the evaluation of civil aircraft noise, which is considered as a notable characteristic of military aircraft noise. SEL is proved as a suitable noise metric for the measuring military aircraft noise of various flight pattern considering the duration time of noise event. This study reviews whether SEL is a suitable for measuring civil aircraft noise and study shows SEL is fairly compensating the duration time of civil aircraft noise event for the evaluation of aircraft noise. Noise metric for the evaluation aircraft noise based on SEL is more appropriate than based on $L_{MAX}$ for compensating duration time of noise event either military aircraft or civil aircraft. In this reason, current formula of WECPNL based on energy average of measured $L_{MAX}$ for the evaluation of aircraft noise impact in 'Test Method of Noise and Vibration of Korea' is recommended to be amended to formula of WECPNL based on energy average of measured SEL considering compensation of noise event duration time, if WECPNL is not based on measured EPNL, a metric compensating duration time.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.73-80
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• 2007

Modern aircraft are required to carry various external stores mounted at different locations on the wing. Sometimes the attachment of stores to an aircraft wing leads to flutter speed reduction, which is a very severe aeroelastic problem. In order to suppress structural vibration and expand the flutter boundary of the aircraft with stores, it is necessary to investigate the main problems and characteristics of them. In addition, active vibration control may be required because passive vibration isolators show limited capabilities for the various wing/store configuration. In this paper, therefore, the flutter stability to the various wing/store configurations was investigated and active vibration control of wing/store model was performed using a piezoelectric actuator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.5 s.98
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• pp.550-557
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• 2005

Korean 'Law of Aviation' and 'Test Method of Measuring Noise and Vibration' designate to use WECPNL metric based on $L_{max}$ measurement for the accessment of aircraft noise in Korea. However, time duration of noise event can not be considered in $L_{max}$ metric in principle, compensation on the duration has been utilized. A study was done recently to evaluate appropriate duration compensation for the accessment of military aircraft noise under current metric of WECPNL and $L_{max}$. This study was carried out to evaluate what metric is the most appropriate to express aircraft noise including time duration of single noise event, computing and comparing noise exposure with 1 second noise measurement data of military aircraft in $L_{max}$, $L_{Aeq,\;T}$ and SEL. This study shows SEL is the most appropriate noise metric for the evaluation of noise exposure with time duration such as aircraft noise without compensation. It is suggested to use SEL noise metric instead of $L_{max}$ noise metric with duration compensation for the aircraft noise accessment either military aircraft or civilian aircraft.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.59-65
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• 2018

The landing gear (L/G) handle of an aircraft is an essential piece of equipment for aircraft take-off and landing. The bracket in the landing gear handle was fractured during a vibration test when developing the landing gear handle. This paper summarizes the vibration test procedures performed during landing gear handle development. A cause analysis, design improvements, and verification results of the fault in the vibration test are also provided.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.718-723
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• 2003

The number of jet aircraft is increasing. The aircraft noise making people near airports nervous have become a serious social problem. The aircraft noise can be classified into two groups; noise being generated at take-off or landing and noise form run-up test on the ground. In this paper, we consider the aircraft noise from run-up test on the pound and we suggest the noise suppression system.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.587-595
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• 2018

Recently, research is being conducted to use a fuel cell as a power source of unmanned aircraft. However, safety standards about applying fuel cells to unmanned aircraft are insufficient. In this paper, to improve the safety of the fuel cells for unmanned aircraft is experimentally studied. For this reason, standards for safety of fuel cells were analyzed. And influence of vibration among the evaluation items related to the safety of the fuel cell for unmanned aircraft was discussed. In order to, at constant intervals, vibration was applied to the fuel cell, then the performance was measured, the measurement items were gas tightness, polarization curve, frequency response analysis (FRA). A total of 220 hours was experimented at 20 hour intervals. the result of vibration test, gas leakage rate was a maximum of -0.04826 kPa/min and Polarization curve reached a maximum of 1.0103 times of the initial value, the charge transfer resistance reached a maximum of 1.0104 times of the initial value. This research indicate that performance of fuel cell is affected by vibration and this study is expected to contribute to the safety of fuel cell for unmanned aircraft.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.72-77
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• 2011

In this study, the natural frequencies and mode shape of an external mounting pod were verified using the modal analysis and modal testing technique for a pod mounted on an aircraft. The procedure associated with the FEM building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FEM reflecting the results of the modal testing of a pod is built through the optimization, applied to the structural dynamic model of an Aircraft, used to verified the stability of vibration and flutter of an aircraft.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.754-757
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• 2005

Aircraft noise is the serious problem for inhabitants near an air force base. Noise by ground test of aircraft, however, can be minimized through test room construction. In this study, environmental effects of the noise by aircraft ground test were investigated by experiments under the standard act and by performance, prediction of the Hush house, constructed for the noise reduction.