• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.131-134
• /
• 2005

This study examine the annoyance of transportation noise exposure and found the survey method about which noise induces more disturbance or annoyance when more than two kinds of noise exist. This study describes the noise annoyance survey performed in the vicinity of Sin-wol interchange. This residential area was exposed to aircraft noise and traffic noise simultaneously and aircraft noise exposure of this area is about 81 WECPNL, traffic noise exposure is about 81.2 dB(A) nearby road. Noise sources are grouped into three part, traffic noise, aircraft noise and community noise. The questionnaire includes how often, how loud each noise is heard. Also this deals with comparative annoyance reaction from specific noise sources such as aircraft or traffic and its disturbance of daily activities. Facade noise mapping are executed by using a commercial noise mapping software.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.3 s.120
• /
• pp.249-256
• /
• 2007

Aircraft noise is a serious problem to inhabitants near airports. INM is one of programs for determining the predicted noise impact in the vicinity of airports. It has been widely used for engineers to evaluate aircraft noise. However it is difficult to predict aircraft noise in case of lack of exact INM input data. The exact informations about a fighter plane are not known well for a security problem. This study presents methods of reducing errors between measurement and simulation when the exact INM input data is not known. Especially we adjusted the thrust force of aircraft engine and reduced the error.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.546-549
• /
• 2004

The T-50/A-50 Golden Eagle was developed for a supersonic trainer and light combat aircraft. At the design stage, vibration control plans were established and applied. For cockpit vibration, crew comfort vibration level was defined by the requirement of MIL-A-8892. It is found that the T-50/A-50 meets the requirement of cockpit vibration from the flight test data analysis. This paper contains the results of cockpit vibration analysis using the flight test data and the results of human vibration analysis lot the pilot inside aircraft. The human vibration level of pilot is increased as dynamic pressure is increased and at the specific high dynamic pressure, the ride comfort indicates 'a little uncomfortable'. Overall analysis results show that the vibration level of T-50/A-50 cockpit is tolerable and not critical for pilot's comfort.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.46 no.9
• /
• pp.767-773
• /
• 2018

In many cases, modern aircraft are equipped with data acquisition system which checks the structural integrity of the aircraft. The analysis of the vibration data collected with the system is generally performed in dependence on a skilled expert who is familiar with aircraft design. Therefore, it is difficult to provide a representative and objective defect identification standard for general users. In this paper, we shows that it is possible to identify the type of maneuvers and faults by using the Principal Component Analysis(PCA) method in the vast vibration data collected during aircraft operation without using the existing aircraft design analysis. We classified the ROK Army aircraft vibration data for maneuvers and faults types, and applied the PCA to the classified data. Our result shows that it is possible to develop an objective maneuver/fault identification method without design analysis for general users.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.78-83
• /
• 2000

Exterior noise generated by the aircraft induces a serious noise pollution near the airport. For the prediction of an exterior noise radiation of aircraft an empirical formula is employed to model the acoustic sources. It is shown that the fan/compressor noise is the most dominant part of the acoustic sources in all cases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.91-96
• /
• 2000

In this paper a simulation program is developed to abate the aircraft noise in the buildings near the airport. This indoor aircraft noise prediction computer program, which is based on the various data and measured results, is useful for the understanding the noise reduction efficiency of the existing buildings as well as for the effective noise abatement method to keep the optimum indoor level for quiet environment.

• Journal of KSNVE
• /
• v.8 no.4
• /
• pp.690-699
• /
• 1998

This paper discusses the techniques, procedures and the results of the ground vibration test(GVT) performed on the development aircraft and the simple procedure of FE model updating technique from the GVT results. The GVT was carried out using random excitation technique with MIMO(Multi-Input-Multi-Output) data acquistion method, and taking full advantage of poly-reference global parameter estimation technique to identify the vibration modes. In dynamic FE modeling, the aircraft was represented by beam elements and all dynamic analysis was performed using MSC/NASTRAN for this model. In updating procedure, the stiffness of the beam model was adjusted iteratively so as to get the natural frequencies and mode shapes close to the GVT results.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.627-628
• /
• 2010

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.6
• /
• pp.495-501
• /
• 2012

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 FE model building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FE model reflecting the results of the modal testing of a pod is built through the optimization and will be applied to the structural dynamic model of an aircraft which is used to verified the stability of vibration and flutter of an aircraft.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.900-904
• /
• 2005

Studies of community annoyance caused by civil aircraft noise exposure were carried out in fifteen areas near Gimpo and Gimhae international airports, Korea, to accumulate social survey data in Korea and to assess the relationship between aircraft noise level and degree of annoyance. Aircraft noise levels were measured automatically by airport noise monitoring system, B&K type 3597. A social survey was carried out people living within In meters of noise measurement points, as a rule. Questionnaires were only aggregated face-to-face interviews using various questions which concerned with demographic, degree of noise annoyance, interference with daily activities and health-related symptoms. The questions of noise annoyance were answered on an 11-point numerical scale. The respondents, from 18 to 70 years of age, were randomly selected and completed the questionnaire themselves. The total number of respondents for the questionnaires was 554.