• Title/Summary/Keyword: Aircraft Noise

Search Result 350, Processing Time 0.084 seconds

An Analysis of the radiation acoustic field of a Aircraft Engine Noise (비행기 엔진 소음의 방사 음향장 해석)

  • 전완호;이재규;이덕주
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 1997.04a
    • /
    • pp.649-655
    • /
    • 1997
  • 본 논문은 항공기의 외부소음 중 엔진에 의한 소음의 전방으로의 방사에 대한 연구이다. 우선 엔진소음의 소음원을 살펴보고 주된 소음원인 압축기/팬 소음을 Tyler & Sofrin의 논문에 의해서 모델한 후 FEM을 이용하여 내부 음원에 의한 외부의 방사음압을 해석하였다.

  • PDF

A study on the estimation of relative shift vector from aerial image sequence and aircraft attitude information (연속 항공영상과 비행체의 자세 정보를 이용한 상대적 편이 추정에 관한 연구)

  • 김종문;박래홍;이쾌희
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1992.10a
    • /
    • pp.147-152
    • /
    • 1992
  • This paper describes a new approach that can extract the relative shift vectors between two aerial image sequences for implementing the visual navigation system. This method minimizes the noise included in the aircraft attitude information that represents the changes of the aircraft attitude using the statistical method and Kalman Filtering method. This result can be used to find the relative shift vectors which are independent of the attitude changes indicating the true trajectories of aircraft. We applied this method to the image about which we had already known the information of aircraft attitude, and that result showed that the errors were minimized successfully.

  • PDF

The Study of Dynamic Safety Using M&S for Integrated Electro-mechanical Actuator Installed on Aircraft (M&S를 이용한 항공기용 통합형 전기식 구동장치의 동적 안전성 연구)

  • Lee, Sock-Kyu;Lee, Byoung-Ho;Lee, Jeung;Kang, Dong-Seok;Choi, Kwan-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.25 no.2
    • /
    • pp.108-115
    • /
    • 2015
  • Electro-mechanical actuator installed on aircraft consists of a decelerator which magnifies the torque in order 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. Electro-mechanical actuator controls aircraft altitude, position, landing, takeoff, etc. It is an important part of a aircraft. Aircraft maneuvering causes vibrations to electro-mechanical actuator. Vibrations may result in structural fatigue. For that reason, it is necessary to analyze the system structural safety. In order to analyze the system structural safety. It is needed reasonable finite element model and structural response stress closed to real value. In this paper, analytic model is derived by using the simplified finite element model, and damping ratio which is closely related to response stress is derived by using modal test. So, we developed analytic model in less than 10 % error rate, compared with modal test. Vibration response stress close to real value was estimated from analytic model modified with modal experimental damping ratio. Estimation method for damping ratio with empirical formula was suggested partly. Finally, It was proved that electro-mechanical actuator had reasonable structure margin of safety at environmental random $3{\sigma}$ stress during life cycle.

The Research on the hearing damage and methods of hearing protection against aircraft noise (항공기 소음으로 인한 청력손실과 보호방안에 관한 연구)

  • Song, Byung-Heum;Choi, YiI-Kyoo
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.3 no.1
    • /
    • pp.21-35
    • /
    • 1995
  • Nowadays aviation noise significantly affects a number of people over the world. This paper is mainly focused on the effect of temporary and permanent hearing loss of cockpit crew, flight attendants, passengers, persons in communities exposed to aircraft overflight. Also this paper describes the human hearing mechanism and the processes of temporary and permanent hearing loss. The results of research are presented and the potential for hearing loss in aviation noise environments evaluated. The Occupational Safety and Health Administration (OSHA) hearing protection criteria are also addressed.

  • PDF

Aircraft Engine Performance Test Technologies by 150K lbf Thrust Test Cell (15만 파운드급 테스트 셀을 이용한 엔진성능 시험기술)

  • Kim, Woocheol;Kim, Chul;Kim, Sangbaek
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2017.05a
    • /
    • pp.180-187
    • /
    • 2017
  • Major design targets such as test cell type, cell flow, cell bypass ratio, approach velocity, cell depression, front cell distortion, noise level and vibration level to construct a new 150,000 lbf thrust aircraft engine test facility were established. Based on the final aerodynamic and acoustic performance tests conducted at the newly constructed test facility, it was found that the new test facility is judged to be excellent and meets design targets.

  • PDF

Enhancement of the Ultrasonic Image Using the Adaptive Window Log Filter for NDI of Aircraft Composite Materials (항공기 복합 재료의 비파괴 검사(NDI)를 위한 가변 창 필터를 이용한 초음파 영상 개선)

  • Hong, G.Y.;Hong, S.B.
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.11 no.2
    • /
    • pp.33-42
    • /
    • 2003
  • In this paper, we propose an enhancement of the ultrasonic image for non-destructive inspection of aircraft composite materials. The ultrasonic images are corrupted by a speckle noise which has the characteristic of granular pattern noise and is in all types of coherent imaging systems, the signal independent and multiplicative noise. In this paper, we derive a filter, called the AWLF(Adaptive Window Log Filter), from the nature of the speckle. The filter is made of the MEAN Filter in the edge region and Log Filter in the flat or noise region. To make a distinction between edge and flat region, we calculate the inclination around the local window instead of computing the local statistics of pixels such as local mean ${\bar{M}}$ and standard deviation ${\sigma}_s$. According to the obtained region, edge region is performed by the mean filter and flat region by the Log filter. Performance of the proposed filter is evaluated by the Enhanced Factor$(F_e)$ and the Speckle Index(SI).

  • PDF