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전기 유동유체를 함유하는 지능외팔보의 진동특성 및 제어 실험적 고찰
최승복,박용군,서문석,Choi, Seung-Bok,Park, Yong-Kun,Suh, Moon-Suk 대한기계학회 1993 대한기계학회논문집 Vol.17 No.7
This paper reports on a proof-of-concept experimental investigation focused on evaluating the vibration characteristics and control of smart hollow cantilever beams filled with an electro-rheological(ER) fluid. The beams are considered to be of uniform viscoelastic materials and modelled as a viscously-damped harmonic oscillator. Electric field-dependent natural frequencies, loss factors and complex moduli are evaluated and compared among three different beams : two types of different volume fraction of ER fluid and one type of different particle concentration of ER fluid by weight. Modal characteristics of the beams are observed in both the absence and the presence of electric potentials. It is also shown that by constructing active control algorithm the removal of structural resonances and the suppression of tip deflection are obtained. This result provides the feasiblility of ER fluids as an active vibration control element.
이산시간 퍼지-슬라이딩모드를 이용한 스마트구조물의 강건진동제어
최승복,김명석,Choi, Seung-Bok,Kim, Myoung-Suk 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.11
This paper presents a new discrete-time fuzzy-sliding mode controller for robust vibration control of a smart structure featuring a piezofilm actuator. A governong equation of motion for the smart beam structure is derived and discrete-time codel with mismatched uncertainties such as parameter variations is constructed ina state space. A discrete-time sliding mode control system consisting of an equivalent controller and a discontinuous controller is formulated. In the design of the equivalent part, so called an equivalent controller separation method is adopted to achieve vzster convergence to a sliding surface without extension of a sliding region, in which the system robustness maynot be guaranteed. On the other hand, the discontinuous part is constructed on the basis of both the sliding and the convergence conditions using a time-varying feedback gain. The sliding moide controller is then incorporated with a fuzzy technique to appropriately determine principal control parameters such as a discountinuous feedback gain. Experimental implementation on the forced and random vibraiton controls is undertaken in order to demonstrate superior control performance of the proposed controller.
최승복(Seung Bok Choi),김완호(Wan Ho Kim),박진혁(Jinhyuk Park),칼루반 수레쉬(Kaluvan Suresh) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10
A novel Permanent Magnet based Magneto Rheological (PM-MR) damper is proposed in this paper. The principle of proposed MR damper is achieved by designing a linearly varying magnetization area with-respect to the movable permanent magnetic based piston setup. Nowadays, commercially available MR damper uses electromagnetic coils for generating the variable magnetic fields corresponding to the variable damping force. The amount of magnetic field produced by the electromagnetic coils are depends on the biasing current of voltage source. The key enabling concept of the proposed MR damper is to replace the electromagnetic coils and the voltage sources by utilizing the variable area based permanent magnetic piston setup. The proposed unique design structure of PM-MR damper has an increasing shear mode damping force with the piston movement in both jounce and rebound motion. In this research, analytical model of the proposed structure is derived and the structural design of proposed concept is verified using numerical CAD tool. As a result, the damping force is increase when piston movement in both jounce and rebound motion.
최승복(Choi, Seung-Bok),오부열(Oh, Bu-Yeol),최돈묵(Choi, Don-Mook) 한국화재소방학회 2011 한국화재소방학회 학술대회 논문집 Vol.2011 No.추계
심하게 소손된 화재현장은 남아 있는 잔존물만으로 초기 화재의 유형을 판단하기 곤란할 때가 많다. 화재로 인해 사람이 사망하였을 경우 혈중 일산화탄소-헤모글로빈 농도는 생존 당시의 화재의 유형을 가늠할 수 있으며 촉진제를 사용한 급격한 화재의 경우 열기와 유독가스로 인해 재실자의 생존은 화재진행속도와 비례되어 체내 헤모글로빈 일산화탄소 농도는 낮았으며, 훈소와 같이 서서히 진행되는 연소의 경우 오랜 시간 호흡하면서 체내에 축적되는 일산화탄소 농도는 증가하였다. 이러한 인체의 헤모글로빈-일산화탄소 농도를 분석하면 생존 시 어떠한 형태의 화재에 노출되었는지 알 수 있었다. Fire patterns have been used to determine the origin and cause of fires in every setting imaginable. However, it is very difficult to identify fire patterns from the fire-damaged remains of a devastated structure. If someone was killed by the fire, it is possible to identify fire patterns by analyzing the concentration of carbon monoxide-hemoglobin in the body of deceased as well as the pace of the fire. For example, a low level of carbon monoxide-hemoglobin in the body of the dead indicates a rapid fire with accelerants and the death was caused by severe heat and thick toxic fumes. However, a high level of carbon monoxide-hemoglobin in the body of the dead demonstrates that the fire was slow and/or there was a flameless form of combustion. Thus, this study identifies fire patterns through analyzing the level of carbon monoxide-hemoglobin concentration on the dead from the fire.