• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.889-898
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• 2008

In this study, analyze the status and problem of a noise and vibration control laws of it through the questionnaire. The method of survey was made by questionnaires which were the civil worker 138 persons and civil servant 132 persons. Based on this survey, we suggest a improvement of the noise and vibration control laws.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.185-189
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• 2009

It is very important to control the vibration transmitted from external utilities and the transient response due to the internal sources for the precision equipment, which is very sensitive to the vibration environment. The anti-vibration tables that use air springs have been widely used due to their excellent isolation performance, but the systems with high flexibility have the critical problem of large transient response by the impulsive force of the moving mass in operation of the equipment. In this paper, the hybrid vibration control system is proposed, which is combined the air springs with the semi-active MR dampers in order to satisfy the performances of isolation and vibration reduction simutaneously.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.459-464
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• 2001

Vibration control of a plate using an optical fiber sensor and a PZT actuator is considered in this study. An aluminum plate with attached Extrinsic Fabry-Perot Interferometer (EFPI) and PZT actuator is prepared for experimental investigation. Vibration level of EFPI that can represent the mechanical strain without severe distortion is validated by forced vibration experiment. A numerical model of the plate is constructed based on the experimentally obtained frequency responses, and an optimal controller is designed for the multi-modal vibration suppression. It is found that the vibration level of the first three modes can be greatly reduced. The effect of low-pass filtering used to eliminate high frequency noise on the stability and control performance is also considered.

• Earthquakes and Structures
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• 제4권1호
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• pp.11-39
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• 2013

Since slender structures such as utility poles, radio masts, and chimneys, are essentially statically determinate structures, they often collapse during earthquakes. Although vibration control is the most logical method for improving the earthquake resistance of such structures, there are many practical problems with its implementation due to their very long natural vibration period. This paper proposes a new vibration control device to effectively prevent the collapse of slender structures subjected to strong earthquakes. The device consists of a pendulum, an elastic restraint and a lever, and is designed such that when it is attached to a slender structure, the second vibration mode of the structure corresponds to the first vibration mode of the same structure without the device attached. This is highly effective in causing the transverse motions of the device and the structure to oppose each other and so reduce the overall transverse vibration during an earthquake. In the present paper, the effectiveness of the vibration control device is first evaluated based on laboratory experiments and numerical studies. An example of applying the device to a tall chimney is then simulated. A new dynamic analytical method for slender structures with abrupt rigidity variations is then proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.466-471
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• 2008

Structural vibration and noise are hot issues in underwater vehicles such as submarines for their survivability. Therefore, active vibration and noise control of submarine, which can be modeled as hull structure, have been conducted by the use of piezoelectric materials. Traditional piezoelectric materials are too brittle and not suitable to curved geometry such as hull structures. Therefore, advanced anisotropic piezoceramic actuator named as Macro-Fiber Composite (MFC), which can provide great flexibility, large induced strain and directional actuating force is adopted for this research. In this study, dynamic model of the smart hull structure is established and active vibration control performance of the smart hull structure is evaluated using optimally placed MFC. Actuating performance of MFC is evaluated by finite element analysis and dynamic modeling of the smart hull structure is derived by finite element method considering underwater condition. In order to suppress the vibration of hull structure, Linear-Quadratic-Gaussian (LQG) algorithm is adopted. After then active vibration control performance of the proposed smart hull structure is evaluated with computer simulation and experimental investigation in underwater. Structural vibration of the hull structure is decreased effectively by applying proper control voltages to the MFC actuators.

• 한국소음진동공학회논문집
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• 제19권2호
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• pp.138-145
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• 2009

Structural vibration and noise are hot issues in underwater vehicles such as submarines for their survivability. Therefore, active vibration and noise control of submarine, which can be modeled as hull structure, have been conducted by the use of piezoelectric materials. Traditional piezoelectric materials are too brittle and not suitable to curved geometry such as hull structures. Therefore, advanced anisotropic piezocomposite actuator named as Macro-Fiber Composite(MFC), which can provide great flexibility, large induced strain and directional actuating force is adopted for this research. In this study, dynamic model of the smart hull structure is established and active vibration control performance of the smart hull structure is evaluated using optimally placed MFC. Actuating performance of MFC is evaluated by finite element analysis and dynamic modeling of the smart hull structure is derived by finite element method considering underwater condition. In order to suppress the vibration of hull structure, Linear Quadratic Gaussian(LQG) algorithm is adopted. After then active vibration control performance of the proposed smart hull structure is evaluated with computer simulation and experimental investigation in underwater. Structural vibration of the hull structure is decreased effectively by applying proper control voltages to the MFC actuators.

• 소음진동
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• 제6권2호
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• pp.215-224
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• 1996

Active vibration control is generally used to reduce vibration level by the actuators based on measured signal. Dynamic properties of a structure can be easily modified by the active vibration control, so that the vibration level may be effectively reduced to the magnitude below the allowable limit over a wide frequency rangs. In this paper, an instantaneous optimal control algorithm including acceleration feedback is presented for the active vibration control of large structures considering facts that the acceleration response can be easily measured, but the displacement and velocity response are obtained by numerically integrating the measured acceleration response with some errors. The adverse effect of the time delay is overcomed by taking into account the dynamic characteristics of an actuator and filters in the design of controller. Performance test is carried out using a hydraulic active mass driver on a test structure$(L{\times}W{\times}H;=;1200mm{\times}800mm{\times}1600mm, about;500kg)$ supported by four columns under base excitations. It is confirmed that the vibration level of the test structure are reduced to about 1/6 near resonance.

• 한국소음진동공학회논문집
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• 제18권10호
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• pp.1006-1013
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• 2008

In this study, it is outlined that heavy weight floor impact noise induced by the vibration of slab can be reduced using multi tuned mass damper(MTMD) effectively. Substructure synthesis is utilized to develope analytical model of the slab coupled with MTMD and acoustic power is introduced to evaluate the performance of noise control for simplicity. Numerical analysis is carried out to investigate the effect of the properties of MTMD on the vibration and noise control of the simply supported slab. Numerical analysis shows that mass ratio of MTMD is critical on the vibration and noise control of the slab and it is also essential to reduce the vibration in higher modes of slab in the light of its great effect on the radiation of sound.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.781-787
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• 2009

This research is concerned with the application of the active linear actuator to the active vibration control of structure. The active linear actuator will be mounted on the sub-frame so that it can cancel the excitation transferred from the engine. Accelerometer mounted on the sub-frame detects the vibration and its signal is fed into the DSP controller where the control algorithm is installed. The output of the DSP controller is connected to the driver which amplifies the DSP output. In general, the pulse width modulation power amplifier is used to drive the voice-coil type actuator. This study shows the dynamic characteristics of the active linear actuator and active vibration control experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.639-644
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• 2009

This research is concerned with the application of the active linear actuator to the active vibration control of structure. The active linear actuator will be mounted on the sub-frame so that it can cancel the excitation transferred from the engine. Accelerometer mounted on the sub-frame detects the vibration and its signal is fed into the DSP controller where the control algorithm is installed. The output of the DSP controller is connected to the driver which amplifies the DSP output. In general, the pulse width modulation power amplifier is used to drive the voice-coil type actuator. This study shows the dynamic characteristics of the active linear actuator and active vibration control experimental results.