Tuned Vibration Absorber Research Articles

Tunable Active Vibration Absorber: The Delayed Resonator

This paper elaborates upon a novel concept, the Delayed Resonator, a tunable active vibration absorber. This technique uses a control which has a time delayed feedback of the absorber mass displacement. The substance of this process is in that the absorber completely removes oscillations from the primary structure. Two very strong features that should be mentioned are: (a) the excitation frequency range can vary over a semi-infinite interval, and (b) the absorber can be tuned in real time. These are the unique characteristics of the technique distinguishing it from the others. Stability issues of the primary system combined with the Delayed Resonator are addressed following Nyquist and root locus methods. In particular, the absorption performance for cases with time varying excitation frequency is studied. The primary focus of this paper is on the analysis of transient absorption behavior of the Delayed Resonator during its tuning. An example case is provided which considers a step change in the excitation frequency. A well-pronounced manifestation of the tunability feature of the Delayed Resonator is observed. The superiority of the Delayed Resonator absorber over the conventional a priori tuned absorbers is also demonstrated.

Passive, Adaptive and Active Tuned Vibration Absorbers—A Survey

An overview of the recent development of tuned vibration absorbers (TVAs) for vibration and noise suppression is presented. The paper summarizes some popular theory for analysis and optimal tuning of these devices, discusses various design configurations, and presents some contemporary applications of passive TVAs. Furthermore, the paper also presents a brief discussion on the recent progress of adaptive and semi-active TVAs along with their on-line tuning strategies, and active and hybrid fail-safe TVAs.

Passive, Adaptive and Active Tuned Vibration Absorbers—A Survey

An overview of the recent development of tuned vibration absorbers (TVAs) for vibration and noise suppression is presented. The paper summarizes some popular theory for analysis and optimal tuning of these devices, discusses various design configurations, and presents some contemporary applications of passive TVAs. Furthermore, the paper also presents a brief discussion on the recent progress of adaptive and semi-active TVAs along with their on-line tuning strategies, and active and hybrid fail-safe TVAs.

Tuned Vibration Absorbers for “Lively” Structures

In the first part of this paper, the theoretical background and a design procedure for tuned vibration absorbers are presented. In the second part, practical experiences with two footbridges and a ...

Design Considerations for Delayed-Resonator Vibration Absorbers

This paper elaborates on a novel concept, the delayed resonator, as a tunable active vibration absorber with an emphasis on the design features. This technique uses a control that has a time-delayed feedback of the absorber mass displacement. The substance of this process is in that the absorber completely removes oscillations from the harmonically excited primary structure. Seminal features of this method are the excitation frequency range can vary over a \Isemi-infinite interval\N, and the absorber can be \Ituned in real time\N. These characteristics uniquely distinguish it from the other techniques. Stability issues of the primary system combined with the delayed resonator are addressed following Nyquist and root locus methods. In particular, the absorption performance for cases with time-varying excitation frequency is studied. An analysis of transient absorption behavior of the delayed resonator during the tuning phase is presented. An example case is taken that considers a step change in the excitation frequency. The superiority of the delayed-resonator absorber over the conventional a priori tuned absorbers is also demonstrated. The highlight of the paper is at the design aspect of this novel absorber. A selection template is proposed for the designer to achieve a desirable frequency-tuning property for the absorption. A set of simulation verifications is included in the text.

Active damping of self-excited torsional vibrations in oil well drillstrings

A drillstring used for the drilling of oil or gas wells behaves as a rotating torsional pendulum. The drillstring is rotated at a constant angular velocity by an electric motor, but exhibits superimposed torsional vibrations caused by a non-linear relationship between torque and angular velocity at the rock-crushing tool. The vibrations are self-excited, and disappear when the mean angular velocity of the pendulum is raised above a threshold value. An active damping system is described that strongly reduces the threshold value by using feedback control, thus extending the working range for vibration-free rotation. It operates at the current and the voltage of the electric motor, and can be implemented with only electrical components. The active damping system is interpreted as an extension of the passive tuned vibration absorber for quenching of self-excited vibrations in the form of a resilient foundation, as described by Tondl (1975 Journal of Sound and Vibration 42(2), 251–260). The concept of quenching self-excited vibrations by modifying the drive system as described in this paper is directly applicable to other engineering systems which are driven by a separately excited DC motor. Furthermore, the concept can be applied to systems driven by a hydraulic motor with a continuously variable flow rate.

A new tuned vibration absorber for wide-band excitations

The vibration control capability of a modified tuned vibration absorber is investigated. Numerical simulations have shown clearly that using an impact damper may significantly improve the performance of a conventional vibration absorber at its first natural frequency. Attenuations are also observed at the second natural frequency. In addition, the minimal amplitude at the original tuning frequency could be maintained. Experiments performed to check the validity of the numerical approach produced close agreement.

Dynamic vibration absorber

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A New Treatment of the Tuned Absorber with Damping

SummaryThe design of the damped tuned vibration absorber, which has previously been treated algebraically, is studied by the use of a three-dimensional admittance diagram. The advantages of this method are that the basic principles can be more easily understood and that it is not necessary to simplify the vibrating system so much. The results obtained by the use of the method show that under some conditions the algebraic treatment does not give the optimum tuning, but that the differences in performance of dampers which have been designed by the two methods will not be large. It is shown how the method may be extended to more complex problems.