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홍성부 대한건축학회 1991 建築 Vol.35 No.3
우루과이 라운드 서비스부문 협상의 진행과 더불어 건설업의 국제화 개방화는 점차 가시화되고 있으며 이에 따른 국내 건설업계의 능동적, 다각적 대응이 요청되고 있다. 한편 개발사업의 한 분야로서 큰 비중을 차지하는 주택산업 역시 금융시장, 유통시장의 개방, 건설업 개방 등 복합적인 요소에 의해 국제화의 과정을 밟아가고 있으나 예상되는 시장의 규모에 비해 경쟁력을 확보하지 못하고 있는 것이 현 실정이다. 그러나 이번 시장개방을 걱정만 하는 소극적인 자세를 탈피하고 교역의 확대라는 대전제 아래 새로운 시장개척의 호기로 보는 적극적인 사고로 정부로 물론 업계가 유기적인 공동노력을 지소적으로 추진한다면 국내건설산업은 국제화 시대를 맞아 한 단계 도약된 선진국 수준의 건설산업으로 육성될 수 있는 좋은 기회를 맞이했다고 생각한다.
홍성부,이예린,권영민,박재상,김지수,김도형 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.1
A simulation study using an active vibration control system (AVCS) to reduce airframe vibrations of an unmanned compound helicopter is conducted. The present unmanned compound helicopter uses wings, propellers, and a lift-offset coaxial rotor system, with two blades per rotor for high-speed flight. The airframe vibration responses are reduced using the AVCS at 230 knots. The hub vibratory loads of a lift-offset coaxial rotor are calculated using a rotorcraft comprehensive analysis code, CAMRAD II. The obtained rotor vibratory loads excite the airframe structure, represented as a one-dimensional stick (elastic line) model. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics and analyze the vibration response of the airframe. The AVCS in this work uses the Fx-LMS (Filtered-x Least Mean Square) algorithm to determine the vibration cancellation signal produced by the force generators, which has the same amplitude but opposite direction to the airframe vibration signal. Herein, the AVCS consists of four force generators and six accelerometers and the simulation framework is constructed using MATLAB Simulink. Ten AVCS simulations are conducted, considering the different locations and various directions of the vibration cancellation forces from the force generators. When AVCS is applied to the airframe at a flight speed of 230 knots, the 2/rev longitudinal and vertical vibration responses at the specified airframe positions, such as the remote cockpit device, wing root, and wing tip, are reduced by 81.39–99.93%, compared to the baseline results without AVCS application.
고속 비행의 Lift-offset 복합형 헬리콥터 기체의 능동 진동 제어 시뮬레이션
홍성부,권영민,김지수,이유빈,박병현,신현철,박재상,Hong, Sung-Boo,Kwon, Young-Min,Kim, Ji-Su,Lee, Yu-Been,Park, Byeong-Hyeon,Shin, Hyun-Cheol,Park, Jae-Sang 한국군사과학기술학회 2021 한국군사과학기술학회지 Vol.24 No.4
This paper studies the simulations of active airframe vibration controls for the Sikorsky X2 helicopter with a lift-offset coaxial rotor. The 4P hub vibratory loads of the X2TD rotor are obtained from the previous work using a rotorcraft comprehensive analysis code, CAMRAD II. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics of the X2TD airframe and to analyze the 4P vibration responses of the airframe. A simulation study using Active Vibration Control System(AVCS) with Fx-LMS algorithm to reduce the airframe vibrations is conducted. The present AVCS is modeled using MATLAB Simulink. When AVCS is applied to the X2TD airframe at 250 knots, the 4P longitudinal and vertical vibration responses at the specified airframe positions, such as the pilot seat, co-pilot seat, engine deck, and prop gearbox, are reduced by 30.65 ~ 94.12 %.