• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.310.1-310
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• 2002

Dynamic characteristics of smart laminated composite plates with passive constrained layer damping have been investigated to design structure with maximum possible damping capacity. The equations of motion are derived fur flexural vibrations of symmetrical, multi-layer laminated plates. The damping ratio and modal damping of the first bending and torsional modes are calculated by means of iterative complex eigensolution method. (omitted)

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.37-42
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• 2003

Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping have been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.264-271
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• 2006

Stay cables, such as used in cable-stayed bridges, are prone to vibration due to their low inherent damping characteristics. It has been reported that a semiactive control system using MR dampers could potentially achieve both the better performance compared to a passive control system and the adaptability with few of the detractions. However, a control system including a power supply, a controller and sensors is required to improve the control performance of MR dampers. This complicated control system is not effective to most of large civil structures such as long-span bridges and high-rise buildings. This paper proposes a smart damping system which consists of an MR damper and the electromagnetic induction (EMI) part that is considered as an external power source to the MR damper. The control performance of the proposed damping system has been compared with that of the passive-type control systems employing an MR damper and a linear viscous damper.

• 한국공간구조학회논문집
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• 제15권2호
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• pp.105-112
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• 2015

A shared tuned mass damper (STMD) was proposed in previous research for reduction of dynamic responses of the adjacent buildings subjected to earthquake loads. A single STMD can provide similar control performance in comparison with two traditional TMDs. In previous research, a passive damper was used to connect the STMD with adjacent buildings. In this study, a smart magnetorheological (MR) damper was used instead of a passive damper to compose an adaptive smart STMD (ASTMD). Control performance of the ASTMD was investigated by numerical analyses. For this purpose, two 8-story buildings were used as example structures. Multi-input multi-output (MIMO) fuzzy logic controller (FLC) was used to control the command voltages sent to two MR dampers. The MIMO FLC was optimized by a multi-objective genetic algorithm. Numerical analyses showed that the ASTMD can effectively control dynamic responses of adjacent buildings subjected to earthquake excitations in comparison with a passive STMD.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.73-79
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• 2001

압전재료를 이용한 지능패널의 전달음 저감성능을 실험적으로 연구하였다. 제안된 압전지능패널은 압전 감지기와 작동기가 부착되어 있는 주구조물에 흡음재가 한 쪽면에 부착된 구조이다. 이는 저주파에서 능동적 방법과 고주파에서 수동적방법을 혼용한 개념이다. 이 개념을 증명하기 위하여 음향실험을 수행하였다. 음향실험을 위하여 음향터널을 설계, 제작하여 음향특성을 실험하였다. 음향 특성실험을 통하여 800 Hz가지 평면파특성을 나타내었다. 단일패널에 흡음재를 부착한 지능패널은 첫번째 공진주파수영역을 제외한 중주파수영역에서 뚜렸한 소음저감성능을 나타내었다. 첫번째 공진주파수에 대하여 반전회로를 이용한 능동제어를 수행하여 약 10 dB소음저감을 이루었다. 또한, 공기층을 갖는 이중지능패널에 대한 실험을 통하여 공진주파수에서 뿐만 아니라 넓은 영역에서 좋은 소음저감성능을 보였다. 수동적 방법과 능동적 방법을 혼용한 압전지능패널은 넓은 주파수 영역에서의 소온저감대책으로 유망한 기술이다.

• Smart Structures and Systems
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• 제15권3호
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• pp.831-846
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• 2015

Magneto-Rheological (MR) dampers are being used increasingly because of their adaptability to control algorithms and reliability of passive systems. In this paper, an extensive investigation on performance of MR dampers in semi-active and passive modes has been carried out. It is observed that the overall energy dissipation by MR dampers in passive-on modes is higher than that in semi-active modes for most of the competitive semi-active controllers. Based on the energy dissipation pattern, a novel semi-active controller, termed as "Simple Passive Semi-Active Controller", has been proposed for MR dampers. This controller can be emulated by a simple passive hardware proposed in this paper. The proposed concept of controller "hardware emulation" is innovative and can also be implemented for other semi-active devices for control algorithms of certain form. The effectiveness and reliability of the proposed controller has been investigated extensively through numerical simulations. It has been demonstrated that the proposed controller is competitive to or more effective than other widely used / investigated semi-active controllers.

• Smart Structures and Systems
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• 제20권5호
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• pp.637-640
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• 2017

The adoption of cladding panels as dissipation device is a sort of passive control "ante litteram" for residential and commercial buildings. This paper gives details on the current technology outlining the difference between buffer panels and cladding panels. The discussion of robustness and resilience of the resulting system is afforded. It is shown that the strength of such solution, originally related to economy and light weight, is mainly associated with the respect of the main robustness requisites, as well as the short time it requires for removal and replacement (resilience).

• Smart Structures and Systems
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• 제1권3호
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• pp.235-256
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• 2005

The non-linear behaviour of electrorheological (ER) and magnetorheological (MR) dampers makes it difficult to design effective control strategies, and as a consequence a wide range of control systems have been proposed in the literature. These previous studies have not always compared the performance to equivalent passive systems, alternative control designs, or idealised active systems. As a result it is often impossible to compare the performance of different smart damper control strategies. This article provides some insight into the relative performance of two MR damper control strategies: on/off control and feedback linearisation. The performance of both strategies is benchmarked against ideal passive, semi-active and fully active damping. The study relies upon a previously developed model of an MR damper, which in this work is validated experimentally under closed-loop conditions with a broadband mechanical excitation. Two vibration isolation case studies are investigated: a single-degree-of-freedom mass-isolator, and a two-degree-of-freedom system that represents a vehicle suspension system. In both cases, a variety of broadband mechanical excitations are used and the results analysed in the frequency domain. It is shown that although on/off control is more straightforward to implement, its performance is worse than the feedback linearisation strategy, and can be extremely sensitive to the excitation conditions.

• Smart Structures and Systems
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• 제7권5호
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• pp.417-432
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• 2011

The present paper is devoted to vibration canceling and shape control of piezoelastic slender beams. Taking into account the presence of electric networks, an extended electromechanically coupled Bernoulli-Euler beam theory for passive piezoelectric composite structures is shortly introduced in the first part of our contribution. The second part of the paper deals with the concept of passive shape control of beams using shaped piezoelectric layers and tuned inductive networks. It is shown that an impedance matching and a shaping condition must be fulfilled in order to perfectly cancel vibrations due to an arbitrary harmonic load for a specific frequency. As a main result of the present paper, the correctness of the theory of passive shape control is demonstrated for a harmonically excited piezoelelastic cantilever by a finite element calculation based on one-dimensional Bernoulli-Euler beam elements, as well as by the commercial finite element code of ANSYS using three-dimensional solid elements. Finally, an outlook for the practical importance of the passive shape control concept is given: It is shown that harmonic vibrations of a beam with properly shaped layers according to the presented passive shape control theory, which are attached to an resistor-inductive circuit (RL-circuit), can be significantly reduced over a large frequency range compared to a beam with uniformly distributed piezoelectric layers.

• 한국지진공학회논문집
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• 제9권1호통권41호
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• pp.51-59
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• 2005

본 연구에서는 위의 어려움을 해결하기 위해, 스마트 수동제어 시스템을 제안하였다. 스마트 수동제어 시스템은 MR댐퍼와 EMI시스템으로 구성되며, EMI시스템은 영구자석과 솔레노이드 코일로 이루어진다. EMI시스템은 MR댐퍼의 왕복운동에너지를 전기에너지로 변환하므로, 스마트 수동제어 시스템은 외부 전원 없이 외부하중에 따라 댐퍼의 점성을 바꾸는 적응성을 갖는다. 따라서 간단하고 효율적인 장치로써, 대형토목구조물에 적용 가능하다. 이의 확인을 위해 예제를 통한 수치해석을 수행하였으며, 스마트 수동제어 시스템이 강진에 대해서는 기존의 반능동 제어 MR댐퍼 시스템 보다 우수한 성능을 보인다.