• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.47-55
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• 2003

This paper Presents active control algorithm using probability density function of structural energy. It is assumed that the structural energy under excitation has Rayleigh probability distribution. This assumption is based on the fact that Rayleigh distribution satisfies the condition that the structural energy is always positive and the occurrence probability of minimum energy is zero. The magnitude of control force is determined by the probability that the structural energy exceeds the specified target critical energy, and the sign of control force is determined by Lyapunov controller design method. Proposed control algorithm shows much reduction of peak responses under seismic excitation compared to LQR controller, and it can consider control force limit in the controller design. Also, chattering problem which sometimes occurs in Lyapunov controller can be avoided.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.56-59
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• 2003

As the slab is longer and lighter, it is more sensitive to the external force so that the vibration of slab and noise induced by the slab vibration is bigger than expected in normal slab. The purpose of this study is to investigate how the dynamic characteristic of slab is different from the normal slab through the system identification and tn evaluate the vibration control performance when the damper system is installed. Finally, we was trying to understand by what mechanism the slab noise is induced from the slab vibration. The relationship between the vibration and the noise of slab is shown by the numerical simulation.

• Journal of the korean Society of Automotive Engineers
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• v.16 no.5
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• pp.1-9
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• 1994

여기에서는 승용차의 구성부품별 해석기술의 분야별로 기술동향을 찾아보고자 한다. 1. 엔진과 변속장치 분야. 1.1 파워 플랜트 강성. 1.2 음원대책. 1.3 미션분야. 2. 흡.배기계 분야. 2.1 흡.배기음. 2.2 실내소음. 3. 엔진 마운팅 분야. 3.1 마운팅 레이아웃. 3.2 마운팅 특성. 3.3 전자제어 마운팅. 4. 타이어.서스펜션 분야. 4.1 서스펜션. 4.2 타이어. 5. 보디,프레임 분야. 5.1 보디구조. 5.2 실내음. 5.3 풍절은과 그외의 음. 5.4 경량 고강성. 6. 진동.소음실험 기술분야. 6.1 계측기술. 6.2 센서. 6.3 실험 시뮬레이션. 6.4 감성의 정량화. 7. 시뮬레이션 해석 분야. 7.1 적용범위. 7.2 복합 시뮬레이션. 7.3 모델화. 7.4 감성 시뮬레이션.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.266-271
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• 1996

Optimal design of disk shaped piezoelectric actuator and sensor mounted on the plate structure is studied for the control of noise radiated fro the structure. The sensor signal is returned to the actuator through negative gain. Finite element modelling is used for the plate structure and the disk shaped piezoelectric sensor and actuator. The objective function is the total radiated sound power and the design variables are the locations and sizes of the piezoelectric actuator and sensor. The optimal is performed at the resonance and the off resonance frequency and the results show good noise reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.445-450
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• 1997

Optimal design of a piezoelectric smart structure is studied for cabin noise control. A cubic shaped acoustic cavity with a flat plate which covers one side is taken as the problem. The sensor signal is returned to the actuator through a negative gain. The acoustic cavity is modeled using the modal approach which represents the pressure fields in the cavity as a sum of mode shapes of the cavity with unknown coefficients. By using orthogonality of the mode shapes of the cavity, finite element equation for the structure with the influence of the acoustic cavity is derived. The objective function is the average pressure at a certain region, so-called silent zone, in the cavity and the design variables are the locations and sizes of the piezoelectric actuator and sensor. The optimal design is performed at several frequencies and the results show a remarkable noise reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.674-679
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• 2000

This research is concerned with the modeling technique and active vibration controller design for slewing smart structures. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates from the initial stage of slewing, In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. It is found from experiments that the theoretical model lacks the frictional effect. The frictional effect is incorporated into the equations of motion by employing the coupling factor. Theoretical and experimental results show problems arising in modeling and controller design.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.435-443
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• 2010

This study presents key parameters for the structure installed with MR controller in reducing its responses. MR controller is regarded as Bingham model of which control forces are frictional and viscous ones. The parameters are identified as friction force ratios, $R_f$ and $R_h$ which are, respectively, ratio of MR controller friction force to static restoring force for free vibration and ratio of the friction force to amplitude of harmonic force. Structure-MR controller system shows nonlinear response behavior due to friction force. Energy balance strategy is adopted to transform the behavior to linear one with equivalent damping ratio. Finally, proposed equivalent linear process is compared to the nonlinear one, which turns out to give acceptably good results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.139-145
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• 2018

An outrigger system is used widely to increase the lateral stiffness of high-rise buildings, resulting in reduced dynamic responses to seismic or wind loads. Because the dynamic characteristics of earthquake or wind loads are quite different, a smart vibration control system associated with an outrigger system can be used effectively for both seismic and wind excitation. In this study, an adaptive smart structural control system based on an outrigger damper system was investigated for the response reduction of multi-hazards, including seismic and wind loads. A MR damper was employed to develop the smart outrigger damper system. Three cities in the U.S., L.A., Charleston, and Anchorage, were used to generate multi-hazard earthquake and wind loads. Parametric studies on the MR damper capacity were performed to investigate the optimal design of the smart outrigger damper system. A smart control algorithm was developed using a fuzzy controller optimized by a genetic algorithm. The analytical results showed that an adaptive smart structural control system based on an outrigger damper system can provide good control performance for multi-hazards of earthquake and wind loads.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.210-214
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• 2005

The objective of this study is design and structural analysis of crusher for useless wood. Structural analysis and modal analysis were effected in ANSYS and the structural safety was examined in search of displacement, stress, strain. There are avoid to resonance phenomenon by motor control.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.156-161
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• 1992

Over the past twenty years, the concept of structural control has been investigated for the application to large civil engineering structures. At the early years, passive control systems, such as tuned mass damper(TMD) and tuned liquid mass bamper(TLD), have been utilized to reduce the wind induced vibrations of tall buildings, decks and pylons of long-span bridges. More recently, the active control concept has been applied to reducing the structural vibration and increasing the human comfortness in tall buildings during strong wind. In this study, the effectiveness of the active tuned mass damper(ATMD) has been investigated for reducing vibration of large structures during strong earthquake. Stochastic optimal control theory has been employed. Example analyses are carried out through analytical simulation studies.