Theoretical Study on Cable’s Vibration Control by Single TMD

2014 ◽  
Vol 935 ◽  
pp. 211-214 ◽  
Author(s):  
Dong Liang ◽  
Ji Xiang Song
Keyword(s):  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Design Parameters ◽  
Stay Cable ◽  
Coupling Vibration ◽  
Modal Damping Ratio ◽  
Modal Damping ◽  
Vibration Model ◽  
Mass Damper ◽  
Complex Models

The commonly used viscous dampers for cable’s vibration mitigation have some unfavorable factors, such as the damping effect is not obvious for super long stay cable, the limitation of installation position, coupling vibration, etc. The cable-tuned mass damper system vibration model is put forward to solve this problem. The optimal cable-tuned mass damper system modal damping ratio and optimum design parameters, including cable vibration order, TMD’s stiffness, TMD’s mass, and TMD’s damping, were obtained by the method of complex models. The results can provide important reference for the design of TMD for stay cable.

Robust multi-objective optimization design of active tuned mass damper system to mitigate the vibrations of a high-rise building

2014 ◽  
Vol 229 (1) ◽  
pp. 26-43 ◽  
Author(s):  
S Pourzeynali ◽  
S Salimi
Keyword(s):  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Robust Design Optimization ◽  
Design Parameters ◽  
Control Force ◽  
Multi Objective ◽  
High Rise ◽  
High Rise Building ◽  
Mass Damper ◽  
Damper Design

In engineering applications, many control devices have been developed to reduce the vibrations of structures. Active tuned mass damper system is one of these devices, which is a combination of a passive tuned mass damper system and an actuator to produce a control force. The main objective of this paper is to present a practical procedure for both deterministic and probabilistic design of the active tuned mass damper control system using multi-objective genetic algorithms to mitigate high-rise building responses. For this purpose, extensive numerical analyses have been performed, and optimal robust results of the active tuned mass damper design parameters with their effectiveness in reducing the example building responses have been presented. Uncertainties, which may exist in the system, have been taken into account using a robust design optimization procedure. The stiffness matrix and damping ratio of the building are considered as uncertain random variables; and using the well-known beta distribution, 50 pairs of these variables are generated. This resulted in 50 buildings with different stiffness matrices and damping ratios. These simulated buildings are used to evaluate robust optimal values of the active tuned mass damper design parameters. Four non-commensurable objective functions, namely maximum displacement, maximum velocity, maximum acceleration of each floor of the building, and active control force produced by the actuator are considered, and a fast and elitist non-dominated sorting genetic algorithm approach is used to find a set of pareto-optimal solutions.

scholarly journals Multidimensional Seismic Control by Tuned Mass Damper with Poles and Torsional Pendulums

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Haoxiang He ◽  
Wentao Wang ◽  
Honggang Xu
Keyword(s):  
Time History ◽  
Tuned Mass Damper ◽  
Design Parameters ◽  
Damping Capacity ◽  
Torsional Angle ◽  
Total System ◽  
Coupling Vibration ◽  
Seismic Control ◽  
History Analysis ◽  
Mass Damper

Due to the eccentric characteristics and the torsional excitation of multidimensional earthquakes, the dynamic response of asymmetry structure involves the translation-torsion coupling vibration and it is adverse to structural performance. Although the traditional tuned mass damper (TMD) is effective for decreasing the translational vibration when the structure is subjected to earthquake, its translation-torsion coupled damping capacity is still deficient. In order to simultaneously control the translational responses and the torsional angle of asymmetry structures, a new type of tuned mass damper with tuned mass blocks, orthogonal poles, and torsional pendulums (TMDPP) is proposed. The translation-torsion coupled vibration is tuned by the movement of the mass blocks and the torsional pendulums. According to the composition and the motion mechanism of the TMDPP, the dynamic equation for the total system considering eccentric torsion effect is established. The damping capacity of the TMDPP is verified by the time history analysis of an eccentric structure, and multidimensional earthquake excitations are considered. The damping effect of the traditional TMD and the TMDPP is compared, and the results show that the performance of TMDPP is superior to the traditional TMD. Moreover, the occasional amplitude amplification in TMD control does not appear in the TMDPP control. The main design parameters which affect the damping performance of TMDPP are analyzed.

Damping of Stay Cable-Passive Damper System with Effects of Cable Bending Stiffness and Damper Stiffness

2012 ◽  
Vol 204-208 ◽  
pp. 4513-4517 ◽  
Author(s):  
Min Liu ◽  
Guang Qiao Zhang
Keyword(s):  
Numerical Analysis ◽  
Damping Ratio ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Passive Damper ◽  
Modal Damping ◽  
Optimal Damping ◽  
Coefficient Increase

In the present paper, the asymptotic solution of modal damping ratio of stay cable-passive damper system with the influence of cable bending stiffness and damper stiffness was derived. Maximum modal damping ratio and corresponding optimal damping coefficient, which indicated the relationships of the characteristics of the damper and the cable bending stiffness was theoretically analyzed to obtain their close solutions. On the basis of these close solutions, numerical analysis of modal damping of stay cable-passive damper system with the effects of cable bending stiffness and damper stiffness was conducted. The numerical and analytical results show that the maximum modal damping ratio decrease and the corresponding damping coefficient increase, when considering the influence of the damper stiffness and the cable bending stiffness.

Calculation on Modal Damping Ratio of Stay Cable Using Nonlinear Friction Damper

2012 ◽  
Vol 538-541 ◽  
pp. 1800-1803
Author(s):  
Hui Ping Wang
Keyword(s):  
Damping Ratio ◽  
Free Vibrations ◽  
Nonlinear Friction ◽  
Friction Damper ◽  
Stay Cable ◽  
Lumped Mass ◽  
Mass Model ◽  
Modal Damping Ratio ◽  
Stay Cables ◽  
Modal Damping

Stay cables of long span cable-stayed bridges are easy to vibrate under wind or wind/rain loads owning to their very low inherent damping. To install cable dampers near to the anchorages of cable has become a common practice for cable vibration control of cable-stayed bridge structures. In this study, the behaviors of a nonlinear frictional type of damper were investigated. The equations of motion of a cable with a friction damper were derived by using a lumped mass model. Then by introducing modal transformation, the analytical solution for the motion equations was obtained. The results show that the friction damper evokes linearly decaying of free vibrations of the cable as long as the damper does not lock the cable. The modal damping ratio of cable with the friction damper is strongly amplitude dependent. Calculation of modal damping ratio can be simplified using control parameter and the maximum modal damping ratio can be obtained. A universal estimation curve is proposed that is similar to linear viscous damper. These studies could provide design basis for the vibration mitigation of stay cables using nonlinear friction.

scholarly journals LQG Control of Along-Wind Response of a Tall Building with an ATMD

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ki-Pyo You ◽  
Jang-Youl You ◽  
Young-Moon Kim
Keyword(s):  
Damping Ratio ◽  
Tall Buildings ◽  
Tuned Mass Damper ◽  
Wind Load ◽  
Tall Building ◽  
Structural Safety ◽  
Design Parameters ◽  
Random Load ◽  
Mass Damper ◽  
Wind Response

Modern tall buildings use lighter construction materials that have high strength and less stiffness and are more flexible. Although this results in the improvement of structural safety, excessive wind-induced excitations could lead to occupant discomfort. The optimal control law of a linear quadratic Gaussian (LQG) controller with an active tuned mass damper (ATMD) is used for reducing the along-wind response of a tall building. ATMD consists of a second mass with optimum parameters for tuning frequency and damping ratio of the tuned mass damper (TMD), under the stationary random load, was used. A fluctuating along-wind load, acting on a tall building, was treated as a stationary Gaussian white noise and was simulated numerically, in the time domain, using the along-wind load spectra proposed by G. Solari in 1993. Using this simulated wind load, it was possible to calculate the along-wind responses of a tall building (with and without the ATMD), using an LQG controller. Comparing the RMS (root mean square) response revealed that the numerically simulated along-wind responses, without ATMD, are a good approximation to the closed form response, and that the reduced responses with ATMD and LQG controller were estimated by varying the values of control design parameters.

Frequency Analysis of the Tuned Mass Damper

2005 ◽  
Vol 72 (6) ◽  
pp. 936-942 ◽  
Author(s):  
Steen Krenk
Keyword(s):  
Natural Frequencies ◽  
Frequency Tuning ◽  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Modal Damping ◽  
Optimal Damping ◽  
Mass Damper ◽  
Dynamic Amplification ◽  
Structural Mass ◽  
Limiting Value

The damping properties of the viscous tuned mass damper are characterized by dynamic amplification analysis as well as identification of the locus of the complex natural frequencies. Optimal damping is identified by a combined analysis of the dynamic amplification of the motion of the structural mass as well as the relative motion of the damper mass. The resulting optimal damper parameter is about 15% higher than the classic value, and results in improved properties for the motion of the damper mass. The free vibration properties are characterized by analyzing the locus of the natural frequencies in the complex plane. It is demonstrated that for optimal frequency tuning the damping ratio of both vibration modes are equal and approximately half the damping ratio of the applied damper, when the damping is below a critical value corresponding to a bifurcation point. This limiting value corresponds to maximum modal damping and serves as an upper limit for damping to be applied in practice.

scholarly journals Theoretical Investigation on the Impact of Two HDR Dampers on First Modal Damping Ratio of Stay Cable

2021 ◽  
Vol 11 (22) ◽  
pp. 10985
Author(s):  
Duy Thao Nguyen ◽  
Duy Hung Vo ◽  
Md. Naimul Haque
Keyword(s):  
Large Amplitude ◽  
Damping Ratio ◽  
Magnetorheological Damper ◽  
Design Parameters ◽  
Friction Damper ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Stay Cables ◽  
High Damping Rubber ◽  
The Impact

Stay cables are one of the vital components of a cable-stayed bridge. Due to their flexible nature, stay cables are vulnerable to external excitation and often vibrate with large amplitude under wind action which leads to the fatigue failure of the cables. To suppress such kind of large amplitude vibration by improving the damping ratio of the cable various dampers such as magnetorheological damper, friction damper; oil damper; or high damping rubber (HDR) damper are utilized and gained popularity over time. This paper focuses on improving the damping ratio of stay cables using a combination of two HDR dampers. First, the theoretical model is formulated considering cable bending stiffness to evaluate the damping effect of cable-HDR dampers system. Then, the impact of various design parameters of HDR dampers on cable damping considering the cable stiffness is performed. The comparative analysis of results shows that the considered parameters such as loss factor, spring factor, and installation location of dampers have much effect on the stay cables damping ratio. Finally, the optimal parameters of the two HDR dampers are proposed for damper design.

Research on the Modal Damping Ratio for Stay Cable with Viscoselasticity Damper in Cable-Stayed Bridges

2013 ◽  
Vol 779-780 ◽  
pp. 671-674
Author(s):  
Shui Sheng Chen ◽  
De Shan Wang
Keyword(s):  
Damping Ratio ◽  
Bending Stiffness ◽  
Complex Eigenvalue ◽  
Stay Cable ◽  
Modal Damping Ratio ◽  
Modal Damping ◽  
Out Of Plane ◽  
Damper Design ◽  
Inclined Angle ◽  
Separation Strategy

Taking the bending stiffness, cable static sag and cable inclined angle into consideration, equations of space free vibration of the cable-damper system are derived in this paper. Joining the variable separation strategy and center difference method, the partial differential equations are discretized in space and a set of complex eigenvalue equations, which are solved by state space method, are derived, and both the maximum modal damping ration and the optimal damper parameter are obtained. Several typical stay cables are investigated for both the in-plane and out-of-plane modes under different cable parameters and damper parameters. The results demonstrate that modal damping ratio for the first in-plane mode is significantly affected by the cable static sag only, but those for the other modes affected by cable sag are slight, and cable static sag do not affect the optimal damper parameter for all modes, however the bending stiffness will changes both the maximum modal damping ratios and the optimal damper parameters. Some valuable suggestions are proposed for the optimal damper design.

scholarly journals Refined Study on Free Vibration of a Cable with an Inertial Mass Damper

2019 ◽  
Vol 9 (11) ◽  
pp. 2271 ◽  
Author(s):  
Zhihao Wang ◽  
Fangfang Yue ◽  
Hao Wang ◽  
Hui Gao ◽  
Buqiao Fan
Keyword(s):  
Flexural Rigidity ◽  
Damping Ratio ◽  
Inertial Mass ◽  
Experimental Results ◽  
Complex Eigenvalue ◽  
Cable Model ◽  
Modal Damping Ratio ◽  
Modal Damping ◽  
Mass Damper ◽  
Actual Design

To accurately predict the optimum supplemental modal damping ratio of the cable and the corresponding size of the inertial mass damper (IMD), combined effects of the cable sag, the cable flexural rigidity, and the boundary conditions on the control performance of the cable with the IMD are well investigated in this refined study. An analytical model of the cable-IMD system considering these effects is developed. The equation of motion of the cable-IMD system is transformed into a complex eigenvalue problem through the finite difference method. Experimental results from a scaled cable model with an IMD are then used to verify theoretical solutions. Three typical cables in actual cable-stayed bridges are selected for case studies. The results show that the theoretically predicted modal damping ratios of the cable with an IMD, taking into account the sag and the flexural rigidity, agree well with those identified from experimental results, while would be often overestimated with a taut-cable model. Moreover, experimental damping ratios of the cable always fall between those theoretically calculated with fixed ends or pinned ends for each case. Finally, to be conservative in actual design, it is recommended to use the cable-IMD system model with fixed ends to calculate the required damper size and predict the resulting modal damping ratio of the cable, since the corresponding theoretical solution often gives the lower bound of supplemental damping ratio of the cable.

Determination of optimal parameters of the tuned mass damper to reduce the torsional vibration of the shaft by using the principle of minimum kinetic energy

2018 ◽  
Vol 233 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Duy-Chinh Nguyen
Keyword(s):  
Kinetic Energy ◽  
Torsional Vibration ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
Tuned Mass Damper ◽  
Optimal Parameters ◽  
Lagrangian Equations ◽  
Tuning Ratio ◽  
Mass Damper

In this paper, an analytical method is presented to determine the optimal parameters of the symmetric tuned mass damper, such as the ratio between natural frequency of tuned mass damper and shaft (tuning ratio) and the ratio of the viscous coefficient of tuned mass damper (damping ratio). The optimal parameters of tuned mass damper are applied to reduce the torsional vibration of the shaft based on consideration of the vibration duration and stability criterion. The dynamic equations of the shaft are provided via Lagrangian equations, and the optimal parameters of tuned mass damper are derived by using the principle of minimum kinetic energy. Analytical and numerical examples are implemented to verify the reliability of the proposed method. The analytical and numerical results indicate that the optimal parameters of tuned mass damper have significant effects in the torsional vibration reduction of the shaft.

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