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.

PERFORMANCE OF DUAL-LAYER MULTIPLE TUNED MASS DAMPERS FOR STRUCTURES UNDER GROUND EXCITATIONS

2006 ◽  
Vol 06 (04) ◽  
pp. 541-557 ◽  
Author(s):  
CHUNXIANG LI
Keyword(s):  
Natural Frequencies ◽  
Vibration Mode ◽  
Frequency Tuning ◽  
Tuned Mass Damper ◽  
Tuned Mass Dampers ◽  
Optimum Parameters ◽  
Generalized System ◽  
Magnification Factors ◽  
Mass Damper ◽  
Multiple Tuned Mass Dampers

The dual-layer multiple tuned mass dampers (DL-MTMD) with a uniform distribution of natural frequencies are proposed, which consist of one large tuned mass damper (L-TMD) and an arbitrary number of small tuned mass dampers (S-TMD). The structure is represented by a generalized system corresponding to the specific vibration mode to be controlled. The criterion for assessing the optimum parameters and effectiveness of the DL-MTMD is based on the minimization of the minimum values of the maximum dynamic magnification factors (DMF) of the structure installed with the DL-MTMD. Also considered is the stroke of the DL-MTMD. The proposed DL-MTMD system is demonstrated to show higher effectiveness and robustness to the change in frequency tuning, in comparison to the multiple tuned mass dampers (MTMD) with equal total mass ratios. It is also demonstrated to be more effective than the dual tuned mass dampers (DTMD) with one large and one small tuned mass damper, but they maintain the same level of robustness to the change in frequency tuning. The DL-MTMD system can be easily manufactured as the optimum value for the linking dashpots between the structure and L-TMD is shown to be zero.

Design and control performance of a frictional tuned mass damper with bearing–shaft assemblies

2019 ◽  
Vol 25 (12) ◽  
pp. 1812-1822 ◽  
Author(s):  
Jinwei Jiang ◽  
Siu Chun Michael Ho ◽  
Nathanael J Markle ◽  
Ning Wang ◽  
Gangbing Song
Keyword(s):  
Damping Ratio ◽  
Excitation Frequency ◽  
Structural Response ◽  
Tuned Mass Damper ◽  
Resonant Peak ◽  
Equivalent Viscous Damping ◽  
Optimal Damping ◽  
Mass Damper ◽  
And Control ◽  
Equivalent Viscous Damping Ratio

This paper explores the feasibility of leveraging the damping generated by the friction between movable flange-mounted ball bearings and a stationary shaft. This bearing–shaft assembly is integrated with a tuned mass damper to form a frictional tuned mass damper (FTMD). The friction coefficient and the equivalent viscous damping ratio of the proposed FTMD were experimentally obtained based on different cases of glass, steel, and aluminum slide shafts. The proposed FTMD was modeled and simulated numerically to study its ability to suppress vibrations on a single degree of freedom structure. Furthermore, a parallel experimental validation of the FTMD was also executed to verify simulation results. Results from both experiments and simulations demonstrated that the proposed FTMD device was able to significantly improve the damping ratio of the primary structure from 0.35% to 5.326% during free vibration, and also to suppress around 90% of uncontrolled structural response at a tuned frequency. In particular, the frequency responses, among the tested shaft materials, suggested that the selected steel slide shaft practically provided a near-optimal damping coefficient, thus the proposed FTMD was able to considerably reduce structural resonant peak amplitudes over the tested excitation frequency domain.

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.

scholarly journals Control Performance and Robustness of Pounding Tuned Mass Damper for Vibration Reduction in SDOF Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Qichao Xue ◽  
Jingcai Zhang ◽  
Jian He ◽  
Chunwei Zhang
Keyword(s):  
Vibration Suppression ◽  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Dynamic Responses ◽  
Control Performance ◽  
Frequency Bandwidth ◽  
Effective Frequency ◽  
Single Degree Of Freedom ◽  
Optimal Damping ◽  
Mass Damper

This paper investigates the control performance of pounding tuned mass damper (PTMD) in reducing the dynamic responses of SDOF (Single Degree of Freedom) structure. Taking an offshore jacket-type platform as an example, the optimal damping ratio and the gap between mass block and viscoelastic material are presented depending on a parametric study. Control efficiency influenced by material properties and contact geometries for PTMD is analyzed here, as well as robustness of the device. The results of numerical simulations indicated that satisfactory vibration mitigation and robustness can be achieved by an optimally designed PTMD. Comparisons between PTMD and traditional TMD demonstrate the advantages of PTMD, not only in vibration suppression and costs but also in effective frequency bandwidth.

scholarly journals Inertial mass damper for vibration control of cable with sag

2018 ◽  
Vol 39 (3) ◽  
pp. 749-760 ◽  
Author(s):  
Zhi-Hao Wang ◽  
Hui Gao ◽  
Bu-qiao Fan ◽  
Zheng-Qing Chen
Keyword(s):  
Inertial Mass ◽  
Damping Coefficient ◽  
Stay Cables ◽  
Modal Damping ◽  
Optimal Damping ◽  
Mass Damper ◽  
Negative Effect ◽  
Supplemental Damping ◽  
Antisymmetric Vibrations ◽  
General Dynamic

It has been theoretically predicted that superior supplemental damping can be generated for a taut cable with an inertial mass damper. This paper extends previous studies to investigate the effect of the cable sag on the efficiency of an inertial mass damper. The general dynamic characteristics of an inclined sag cable with an inertial mass damper installed close to the cable end are theoretically investigated. The parametric analysis of the inertial mass and the damping coefficient of the inertial mass damper are conducted to evaluate the control performance of the cable with different sags. The results show that the inertial mass damper can alleviate the negative effect induced by the cable sag, and the cable sag can even increase modal damping ratios provided by the inertial mass damper. Sags of stay cables used in actual bridges only affect nearly symmetric vibrations of cables, while having little impact on nearly antisymmetric vibrations. The effect of cable sags will reduce the optimal damping coefficient and inertial mass of the inertial mass damper for the first symmetric mode 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.

scholarly journals Development of a Frequency-Adjustable Tuned Mass Damper (FATMD) for Structural Vibration Control

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Huaguo Gao ◽  
Congbao Wang ◽  
Chen Huang ◽  
Wenlong Shi ◽  
Linsheng Huo
Keyword(s):  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Vertical Vibration ◽  
Structural Vibration ◽  
Kinematic Equation ◽  
Pedestrian Bridge ◽  
Long Span ◽  
Mass Damper ◽  
Excitation Frequencies ◽  
Simple Assembly

The tuned mass damper (TMD) can be applied to suppress earthquake, wind, and pedestrian- and machine-induced vibration in factory buildings or large span structures. However, the traditional TMD with a fixed frequency will not be able to perform effectively against the frequency variations in multiple hazards. This paper proposed a frequency-adjustable tuned mass damper (FATMD) to solve this limitation of current TMD. The FATMD presented in this paper is composed of a simple assembly consisting of a supported beam with a mass, in which the frequency of the FATMD is changed by adjusting the span of the beam. The kinematic equation of a single degree of freedom (SDOF) structure installed with an FATMD is established to analyze the effect of the damping ratio, mass ratio, and stiffness on the vibration damping. The fundamental frequency of the FATMD at different spans is verified by simulation and experiments. Forced vibration experiments with different excitation frequencies are also conducted to verify the performance of the FATMD. The results show that the proposed FATMD can effectively suppress the vertical vibration of structures at different excitation frequencies, including frequencies at a range higher than what a traditional TMD may not be able to suppress. Additionally, the proposed FATMD is applied to a long-span pedestrian bridge which vibrates frequently due to the walking of pedestrians, the running of escalators, and earthquakes. The numerical results indicate that the FATMD can effectively reduce the vertical vibration of the pedestrian bridge under the excitations of pedestrians, escalators, and earthquakes.

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.

Mitigation of Vortex-Induced Vibrations of a Pivoted Circular Cylinder Using an Adaptive Pendulum Tuned-Mass Damper

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Sina Kheirkhah ◽  
Richard Lourenco ◽  
Serhiy Yarusevych ◽  
Sriram Narasimhan
Keyword(s):  
Frequency Response ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Tuned Mass Damper ◽  
Single Frequency ◽  
Fundamental Frequencies ◽  
Transverse Vibrations ◽  
Synchronization Region ◽  
Vortex Induced Vibrations ◽  
Mass Damper

A novel adaptive pendulum tuned-mass damper (TMD) was integrated with a two degree-of-freedom (DOF) cylindrical structure in order to control vortex-induced vibrations of the structure. The natural frequency of the TMD was adjusted autonomously in order to control the vortex-induced vibrations. The experiments were performed at a constant Reynolds number of 2100 and for four reduced velocities, 4.18, 5.44, 6.00, and 6.48. Two TMD damping ratios, 0 and 0.24, were investigated for a constant TMD mass ratio of 0.087. The results demonstrate that tuning the natural frequency of the TMD to the natural frequency of the structure decreases the amplitudes of transverse and streamwise vibrations of the structure significantly. Specifically, the transverse amplitudes of vibrations are decreased by a factor of ten and streamwise amplitudes of vibrations are decreased by a factor of three. Depending on the value of the TMD damping ratio, the frequency of transverse vibrations is either characterized by the natural frequency of the structure or by two other fundamental frequencies, one higher and the other lower than the natural frequency of the structure. The results demonstrate that, independent of the TMD damping and tuning frequency ratios, the frequency of streamwise vibrations matches that of the transverse vibrations in the synchronization region, and the cylinder traces elliptic trajectories. A mathematical model is proposed to gain insight into the frequency response of the structure and fluid-structure interactions. The model shows that, for low TMD damping ratios, the frequency response of the structure equipped with the TMD is characterized by two fundamental frequencies; whereas, for relatively high TMD damping ratios, the frequency response of the structure is characterized by a single frequency, i.e., the natural frequency. In both cases, the fluid forcing within the synchronization region is linked to the fundamental frequency/frequencies of the structure. Thus, the classical definition of synchronization applies to multiple DOF structures undergoing vortex-induced vibrations.

scholarly journals Seismic and Wind Analysis of Regular and Irregular RC Structures with Tuned Mass Damper

2019 ◽  
Vol 8 (3) ◽  
pp. 2263-2269
Keyword(s):  
Damping Ratio ◽  
Time History ◽  
Tuned Mass Damper ◽  
Ground Movement ◽  
Building Structures ◽  
Rc Structures ◽  
Dynamic Forces ◽  
Mass Damper ◽  
Rc Building ◽  
The Impact

Latest trend in the development high rise structure demanding taller and lighter structures, which are progressively adaptable with very low damping ratio. As the structures developing vertically, they are ending up all the more affecting by powerful excitation forces, for example, wind and seismic forces. For the more safety of structure and inhabitant's solace, the vibrations of the tall structures become a major issue for both structural designers. So as to control the vibration, various methodologies are proposed out of the few systems accessible for vibration control. Out of numerous methods, TMD has been observed to be increasingly powerful in controlling the dynamic forces caused due to seismic and wind excitations. In this paper, the adequacy of TMD in controlling the dynamic reaction of structures and the impact of different ground movement parameters on the seismic viability of TMD is researched. Essentially, a TMD is a vibratory subsystem appended to a bigger scale host structure so as to lessen the dynamic reactions. The frequency of damper will tuned to essential structure's frequency, so when frequency is high, the damper will results to resonate out of phase along with structural movement. The objective of this work is to study the impact of TMD on the dynamic forces brought about by seismic tremor and wind excitations in standard just as unpredictable in tall RC building structures. For that three 22 story RC building structures are considered with a similar arrangement out of which one ordinary regular structure and the other two are irregular RC structures are demonstrated in Etabs. In irregular RC structures, Stiffness irregularity and torsional irregularity are considered. For assessing seismic and wind reactions of structures, time history analysis, and static analysis used, with and without the tuned mass damper in ETABS. The outcomes acquired from the investigation of three 22 story RC structures with and without tuned mass damper are compared

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