scholarly journals Active Mass Damper for Reducing Wind and Earthquake Vibrations of a Long-Period Bridge

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 66
Author(s):  
Seongkyu Chang
Keyword(s):  
Dynamic Properties ◽  
Damping Ratio ◽  
Harmonic Load ◽  
Control Effect ◽  
Linear Quadratic ◽  
Active Mass ◽  
Long Period ◽  
Bridge Model ◽  
Mass Damper ◽  
Active Mass Damper

An active mass damper (AMD) was developed that uses a linear motor and coil spring to reduce the vertical vibration of a long-period cable-stayed bridge subjected to wind and earthquake loads. A scaled-down bridge model and AMD were fabricated, and the control effect of the AMD was investigated experimentally and analytically. The AMD was controlled via a linear quadratic Gaussian algorithm, which combines a linear quadratic regulator and Kalman filter. The dynamic properties were investigated using a 1/10 scale indoor experimental model, and the results confirmed that the measured and analytical accelerations were consistent. A vibrator was used to simulate the wind-induced vibration, and the experimental and analytical results were consistent. The proposed AMD was confirmed to damp the free vibration and harmonic load and increase the damping ratio of the bridge model from 0.17% to 9.2%. Finally, the control performance of the proposed AMD was numerically investigated with the scaled-down bridge model subjected to the El Centro and Imperial Valley-02 earthquakes. These results were compared with those of a TMD, and they confirmed that the proposed AMD could reduce excessive vertical vibrations of long-period cable-stayed bridges subjected to wind and earthquakes.

scholarly journals Seismic Resistance and Parametric Study of Building under Control of Impulsive Semi-Active Mass Damper

2021 ◽  
Vol 11 (6) ◽  
pp. 2468
Author(s):  
Ming-Hsiang Shih ◽  
Wen-Pei Sung
Keyword(s):  
Frequency Ratio ◽  
Efficiency Index ◽  
Reduction Ratio ◽  
Seismic Resistance ◽  
Control Effect ◽  
Active Mass ◽  
High Rise ◽  
Mass Damper ◽  
Active Mass Damper ◽  
External Forces

When high-rise buildings are shaken due to external forces, the facilities of the building can be damaged. A Tuned Mass Damper (TMD) can resolve this issue, but the seismic resistance of TMD is exhausted due to the detuning effect. The Impulsive Semi-Active Mass Damper (ISAMD) is proposed with fast coupling and decoupling at the active joint between the mass and structure to overcome the detuning effect. The seismic proof effects of a high-rise building with TMD and ISAMD were compared. The numerical analysis results indicate that: (1) the reduction ratio of the maximum roof displacement response and the mean square root of the displacement reduction ratio of the building with the ISAMD were higher than 30% and 60%, respectively; (2) the sensitivity of the efficiency index to the frequency ratio of the ISAMD was very low, and detuning did not occur in the building with the ISAMD; (3) to achieve stable seismic resistance of the ISAMD, its frequency ratio should be between 2 and 4; (4) the amount of displacement of the control mass block of the ISAMD can be reduced by enhancing the stiffness of the auxiliary spring of the ISAMD; and (5) the proposed ISAMD has a stable control effect, regardless of the earthquake distance.

An Algorithm for Parameter Identifications of Active Mass Damper and Primary Systems Based on Acceleration Measurements

2017 ◽  
Author(s):  
Chang-Ching Chang ◽  
Jer-Fu Wang ◽  
Chi-Chang Lin
Keyword(s):  
Time Delay ◽  
State Space ◽  
Active Control ◽  
Dynamic Properties ◽  
Feedback Gain ◽  
Control Force ◽  
Theoretical Derivation ◽  
Active Mass ◽  
Mass Damper ◽  
Active Mass Damper

Active control systems have already been installed in real structures and are able to decrease the wind- and earthquake-induced responses, while the active mass damper (AMD) is one of the most popular types of such systems. In practice, an AMD is generally assembled in-situ along with the construction of a building. In such a case, the AMD and the building is coupled as an entire system. After the construction is completed, the dynamic properties of the AMD subsystem and the primary building itself are unknown and cannot be identified individually to verify their design demands. For this purpose, a methodology is developed to obtain the feedback gain of the AMD controller and the dynamic properties of the primary building based on the complex eigen-parameters of the coupled building-AMD system. By means of the theoretical derivation in state-space, the non-classical damping feature of the system is characterized. This methodology can be combined with any state-space based system identification technique as a procedure to achieve the goal on the basis of the acceleration measurements of the building-AMD system. Results from numerical verifications show that the procedure is capable of extracting parameters and is applicable for AMD implementation practices. In addition, control force execution time delay cannot be avoided in real application of active control. Small delay time can degrade the control performance and may cause system instability. In this study, time delay effect of AMD system is considered in the proposed methodology to obtain the feedback gain of the AMD controller and the dynamic properties of the primary building.

Fundamental Study of Active Mass Damper for Improving Livability of Houses Against Traffic Vibration

2004 ◽  
Author(s):  
Yukito Matsumoto ◽  
Osamu Hasegawa ◽  
Ikuo Shimoda ◽  
Kazuto Seto
Keyword(s):  
Complex Geometry ◽  
Control Effect ◽  
Fundamental Study ◽  
Active Mass ◽  
Response Characteristics ◽  
Population Concentration ◽  
Mass Damper ◽  
Active Mass Damper ◽  
Slender Structure ◽  
External Forces

In Japan, there are many houses built on limited space and also besides side of causeways and railroads, due to population concentration in the cities in recent years. Houses with 3-stories or slender structure houses are susceptible to traffic vibration induced by external forces. This affect frequency creates an uncomfortable environment for habitation. Because houses often have a complex geometry, it is difficult to establish the vibration characteristics of a structure. Furthermore, the response characteristics of a house will change with environmental condition. To address some of these issues, an Active Mass Damper (AMD) has developed in order to supply for users with a reasonable price. This AMD has a mass of 176kg in weight supported by guide springs, and driven by an AC servomotor and a wire rope. The AMD is controlled by two methods, LQ Control and Direct Displacement Feedback (DDFB) Control. In this report, a control effect is examined through simulation when the AMD is installed in the RF level of a 3-story house model. The simulation results are demonstrated that the AMD could improve the uncomfortable environment in houses. A matter of particular note was reduction of about 4 dB in the overall vibration level. Concerning an experimental study about this equipment, refer to the following report, “Fundamental experiment of Active Mass Damper for houses against traffic vibration”.

Optimal Vibration Suppression of Structures Under Random Base Excitation Using Semi-Active Mass Damper

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
F. Yang ◽  
E. Esmailzadeh ◽  
R. Sedaghati
Keyword(s):  
Vibration Suppression ◽  
Mr Damper ◽  
Friction Model ◽  
Structural Vibration ◽  
Linear Quadratic ◽  
Active Mass ◽  
Lugre Friction Model ◽  
Mass Damper ◽  
Active Mass Damper ◽  
Control Methodology

The vibration suppression of structures using a semi-active mass damper is investigated in this study. A magnetorheological (MR)-damper is utilized to design the semi-actively controlled mass damper. The inverse MR-damper model is developed on the basis of an improved LuGre friction model, and combined with a designed H2/Linear-Quadratic-Gaussian (H2/LQG) controller, in order to control the command current of the MR-damper to suppress structural vibration levels effectively. Illustrated examples are considered to investigate the vibration suppression effectiveness of a semi-active mass damper with a MR-damper, using the developed control methodology. The simulation results were compared with those reported in literature in order to validate the presented methodology.

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