• 소음진동
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• 제8권4호
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• pp.700-705
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• 1998

Recent past work has demonstrated that hydraulic semiactive vibration absorbers hold the promise of providing an ideal means of mitigating structural vibration. This paper examines a factor that must be treated when designing a hydraulic semiactive vibration absorber for application to a full scale structure; fluid compressibility. An expanded and consistent dynamic model of the flow process is first established. A simple feedback control is then tested on a single degree of freedom laboratory structure to verify the findings.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.308-315
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• 1997

In this study, the effect of modal filter error on the vibration control characteristics of flexible structures is analyzed for IMSC(Independent Modal Space Control), and optimal sensor placement in the structural vibration control with consideration of performance of modal filter has been studied. An Lyapunov asymptotic stability condition has been derived, which depends on the magnitude of the modal filter errors. The extent of the response deviation of the closed-loop system is also derived and evaluated using operator techniques. A sensor placement technique has also been suggested to maximize the performance of the modal filter. It has been found by a series of simulation that the suggested sensor placement technique is very effective on the determination of the number and placement of sensors of modal filter in the structural vibration control.

• 소음진동
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• 제6권3호
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• pp.317-323
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• 1996

This paper proposes the method of experimental structural dynamic modification of fixture for environmental vibration test control. This method can predict the responses at any points on the fixture utilizing the experimental data, and structural dynamic modification of fixture is made using the predicted responses for the spectra at the specimen attachment points to meet the specified reference spectrum. From the results of controlling the fixture before and after modification by conventional control method and optimal reference spectrum, which has been previously reported by the authors, the proposed method is shown to be an effective one.

• 한국전산구조공학회논문집
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• 제23권6호
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• pp.667-673
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• 2010

Recently, structures are becoming longer and higher because of the developments of new materials and construction techniques. However, such modern structures are more susceptible to excessive structural vibrations which cause deterioration in serviceability and structural safety. A modified probabilistic neural network(MPNN) approach is proposed to reduce the structural vibration. In this study, the global probability density function(PDF) of MPNN is reflected by summing the heterogeneous local PDFs automatically determined in the individual standard deviation of each variable. The proposed algorithm is applied for the vibration control of a three-story shear building model under Northridge earthquake. When the control results of the MPNN are compared with those of conventional PNN to verify the control performance, the MPNN controller proves to be more effective than PNN methods in decreasing the structural responses.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.29-36
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• 1996

A procedure for the predictive control for structural vibration control in building subject to wind loads is presented. The building motions are modeled by the first mode of the response. Wind velocities are generated by the simulation using power spectral density function. Predictive control algorithm is the discrete-time formulation and that is developed as a control strategy that computes the control signal which makes the predicted process output equal to a desired process output. Results on the reduction of the dynamic response and control effectiveness of the algorithm are presented and discussed.

• 한국BIM학회 논문집
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• 제6권3호
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• pp.42-48
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• 2016

Structural members are designed to maintain the load-carrying capacity as well as structural strength, and the structural serviceability such as the deflection, cracks, and vibration to give the occupants uncomfortable environment should be checked. Recently, the importance of the vibration has been issued since the Techno Mart accident due to vibration resonance. This study provides a passive vibration control system using the repulsion force of magnets to reduce dynamic vibrations. The systems is devised by importing the constraint condition by a hinge to operate magnets installed at two adjacent locations. The effectiveness of the proposed system is investigated by the vibration control test of a steel beam with and without the control system. It is illustrated in the test that the system is activated by the control forces executed by the magnets and can be utilized in reducing the dynamic responses. The system can be applied to pedestrian bridge and traffic bridge. The applicability is expected in the future by optimizing the factors to affect the dynamic responses like the intensity, mass, locations of magnets.

• Smart Structures and Systems
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• 제15권3호
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• pp.807-830
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• 2015

When a building structure requires both health monitoring system and vibration control system, integrating the two systems together will be cost-effective and beneficial for creating a smart building structure with its own sensors (nervous system), processors (brain system), and actuators (muscular system). This paper presents a real-time integrated procedure to demonstrate how health monitoring and vibration control can be integrated in real time to accurately identify time-varying structural parameters and unknown excitations on one hand, and to optimally mitigate excessive vibration of the building structure on the other hand. The basic equations for the identification of time-varying structural parameters and unknown excitations of a semi-active damper-controlled building structure are first presented. The basic equations for semi-active vibration control of the building structure with time-varying structural parameters and unknown excitations are then put forward. The numerical algorithm is finally followed to show how the identification and the control can be performed simultaneously. The results from the numerical investigation of an example building demonstrate that the proposed method is feasible and accurate.

• 한국소음진동공학회논문집
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• 제12권9호
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• pp.694-701
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• 2002

In this paper, through the study on locations of structural transducers for active control of the radiated sound from the vibrating plate, the active structural acoustic control (ASAC) system is proposed. And, for the evaluation of the proposed location, the experiment of the active structural acoustic control is implemented using the multi-channel filtered-x LMS algorithm and an additional filter (Acoustic Prediction Filter) to estimate the radiated sound using the acceleration signals of the plate. The structural transducers are piezoceramic actuator (PZT) and accelerometer. PZT is used as an actuator to reduce the vibration and the radiated sound. To maximize the control performance, each PZT actuator is located at the position that has the largest control sensitivity of the plate bending moment in the direction of x and y coordinates and the optimal PZT location is validated experimentally. Also, to find the acoustic prediction filter accurately, two accelerometers are located at the positions that have the largest radiation efficiencies of the plate, and the proposed locations are validated by simulation using the Rayleigh integral. The multi-channel filtered-x LMS algorithm is introduced to control a complex 2-D structural vibration mode. Finding the locations of structural transducers for active structural acoustic control of the radiated sound, the active structural acoustic control (ASAC) system can be presented and validated by experiments using a real time control system.

• Smart Structures and Systems
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• 제2권1호
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• pp.61-80
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• 2006

The concept of structural vibration control is to absorb vibration energy of the structure by introducing auxiliary devices. Various types of structural vibration control theories and devices have been recently developed and introduced into mechanical systems. One of such devices is damper employing controllable fluids such as ElectroRheological (ER) or MagnetoRheological (MR) fluids. MagnetoRheological (MR) materials are suspensions of fine magnetizable ferromagnetic particles in a non-magnetic medium exhibiting controllable rheological behaviour in the presence of an applied magnetic field. This paper presents the modelling of an MRfluid damper. The damper model is developed based on Newtonian shear flow and Bingham plastic shear flow models. The geometric parameters are varied to get the optimised damper characteristics. The numerical analysis is carried out to estimate the damping coefficient and damping force. The analytical results are compared with the experimental results. The results confirm that MR damper is one of the most promising new semi-active devices for structural vibration control.

• 소음진동
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• 제11권1호
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• pp.96-103
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• 2001

지금까지의 여러 연구들에서 유압식 반능동 시스템은 적절하게 동작을 한다면 전능동 유압식 댐퍼 만큼의 구조물 진동저감 능력이 있음을 끊임없이 보여주고 있다. 이 논문에서는 축소 구조물에 설치된 반능동 시스템의 진동저감 성능을 기술하고 있다. 본 논문에서 제안한 시스템의 에너지를 소산시키기 위해 리아푸노브방법을 적용한 바이스테이트 제어의 효과를 수치적 및 실험적으로 입증한 결과들을 먼저 제시한다. 또한 바이스테이트 제어 성능을 다른 두 제어기와 비교 평가하였다. 이 연구결과를 통해 반능동 시스템은 구조물 진동저감에 저렴하면서도 효과적임을 보여준다.