Tunable Active Vibration Absorber: The Delayed Resonator

1995 ◽  
Vol 117 (4) ◽  
pp. 513-519 ◽  
Author(s):  
Nejat Olgac ◽  
Brian Holm-Hansen
Keyword(s):  
Transient Absorption ◽  
A Priori ◽  
Excitation Frequency ◽  
Vibration Absorber ◽  
Primary System ◽  
Active Vibration ◽  
Absorption Performance ◽  
Primary Focus ◽  
Novel Concept ◽  
Stability Issues

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.

scholarly journals Active Vibration Absorber for a Continuous Structure Model

2021 ◽  
Author(s):  
Carlos Gianpaul Rincón ◽  
Jorge Alencastre ◽  
Richard Rivera
Keyword(s):  
Cantilever Beam ◽  
Excitation Frequency ◽  
Element Model ◽  
Continuous Model ◽  
Dynamical Behaviour ◽  
Electrical Circuit ◽  
Vibration Absorber ◽  
Piping System ◽  
Primary System ◽  
Active Vibration

The reduction of mechanical vibrations is field of continuous research in engineering in order to reduce damage and improve the performance of structures, machinery, piping and others systems, when they are in presence of dynamical forces. In this sense, different alternatives have been proposed over time, the active vibration absorber highlights as an alternative which can absorb the vibration from a primary system for different excitation frequency in real time. In this study, an active vibration absorber has been modelled as an electromechanical device composed of a 1-DOF model for the absorber and an equivalent electrical circuit for the electromagnetic actuator. It was implemented in a real structure represented by a cantilever beam continuous model, which is the most accurate model that can be used. A set of differential equations which represent the dynamical behaviour of the cantilever beam implemented with the active vibration absorber was obtained from the complete model and it was simulated in Matlab Simulink®. An application of the active vibration absorber for an industry piping system based on the finite element model formulation is presented and developed. Results indicate that the active vibration absorber is able to significantly reduce the vibrations amplitude of the primary system, especially in resonance conditions, for a discrete frequency range. The analytic model and procedure developed here can easily widespread to any more complex primary system.

On Adaptive-Passive Vibration Suppression Using Distributed-Parameter Absorbers

2000 ◽  
Author(s):  
Nader Jalili
Keyword(s):  
Vibration Suppression ◽  
Excitation Frequency ◽  
Wide Band ◽  
Distributed Parameter ◽  
Vibration Absorber ◽  
Frequency Bandwidth ◽  
Lumped Mass ◽  
Adaptive Capability ◽  
Active Vibration ◽  
Tuning Strategy

Abstract A semi-active vibration absorber with adaptive capability is presented to improve wide band vibration suppression characteristics of harmonically excited structures. The absorber subsection consists of a double-ended cantilever beam carrying an intermediate lumped mass. The adaptive capability is achieved through concurrent adjustment of the position of the moving mass, along the beam, to comply with the desired optimal performance. If such an absorber is attached to a vibrating body, it effectively absorbs vibrations at all frequencies that belong to the absorber frequency bandwidth. Numerical simulations are provided to verify the effectiveness of the proposed absorption scheme. It is shown that the tuning strategy tries to follow and match the absorber natural frequency with the excitation frequency. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and de-tuned absorbers, for wide band excitation disturbances.

Passive/Active Autoparametric Cantilever Beam Absorber With Piezoelectric Actuator for a Two-Story Building-Like Structure

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Gerardo Silva-Navarro ◽  
Hugo F. Abundis-Fong
Keyword(s):  
Cantilever Beam ◽  
Active Vibration Control ◽  
Parametric Uncertainty ◽  
Vibration Absorber ◽  
Primary System ◽  
Internal Resonances ◽  
Piezoelectric Patch ◽  
Active Vibration ◽  
Stiffness And Damping ◽  
Story Building

This work deals with the design and experimental evaluation of a passive/active cantilever beam autoparametric vibration absorber mounted on a two-story building-like structure (primary system), with two rigid floors connected by flexible columns. The autoparametric vibration absorber consists of a cantilever beam with a piezoelectric patch actuator, cemented to its base, mounted on the top of the structure and actively controlled through an acquisition system. The overall system is then a coupled nonlinear oscillator subjected to sinusoidal excitation in the neighborhood of its external and internal resonances. The addition of the piezoelectric patch actuator to the cantilever beam absorber makes active the passive vibration absorber, thus enabling the possibility to control its equivalent stiffness and damping and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty.

scholarly journals Study of Magnetic Vibration Absorber with Permanent Magnets along Vibrating Beam Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
F. B. Sayyad ◽  
N. D. Gadhave
Keyword(s):  
Cantilever Beam ◽  
Gas Turbines ◽  
Permanent Magnets ◽  
Excitation Frequency ◽  
Harmonic Excitation ◽  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Vibratory System ◽  
Electrical Generator

The vibration absorbers are frequently used to control and minimize excess vibration in structural system. Dynamic vibration absorbers are used to reduce the undesirable vibration in many applications such as pumps, gas turbines, engine, bridge, and electrical generator. To reduce the vibration of the system, the frequency of absorber should be equal to the excitation frequency. The aim of this study is to investigate the effect of magnetic vibration absorber along vibrating cantilever beam. This study will aim to develop a position of magnetic vibration absorber along the cantilever beam to adopt the change in vibratory system. The absorber system is mounted on a cantilever beam acting as the primary system. The objective is to suppress the vibration of the primary system subjected to a harmonic excitation whose frequencies are varying. It can be achieved by varying the position of magnetic vibration absorber along the length of beam. The advantage of magnetic vibration absorber is that it can be easily tuned to the excitation frequency, so it can be used to reduce the vibration of system subjected to variable excitation frequency.

Investigation on the phase-based fuzzy logic controller for magnetorheological elastomer vibration absorber

2016 ◽  
Vol 28 (6) ◽  
pp. 728-739 ◽  
Author(s):  
Guojiang Liao ◽  
Yangguang Xu ◽  
Fayuan Wei ◽  
Renwei Ge ◽  
Qiang Wan
Keyword(s):  
Fuzzy Logic ◽  
Control Strategy ◽  
Fuzzy Logic Controller ◽  
Excitation Frequency ◽  
Vibration Absorber ◽  
Primary System ◽  
Magnetorheological Elastomer ◽  
Magnetic Current ◽  
Simulation And Experiment ◽  
Stiffness Control

This article presents a phase-based fuzzy logic controller for magnetorheological elastomer vibration absorber to trace the excitation frequency rapidly. The phase difference between the relative acceleration of the vibration absorber mass and the absolute acceleration of the primary system is used as the input signal of the fuzzy logic controller to calculate the desired magnetic current. Compared with the traditional stiffness control strategy, the proposed controller does not rely on the accurate relationship between the magnetic current and the resonant frequency of the magnetorheological elastomer vibration absorber. Simulation and experiment results demonstrate that the proposed stiffness controller is efficient to make the magnetorheological elastomer vibration absorber trace the excitation frequency rapidly. When the excitation frequency varies, the magnetorheological elastomer vibration absorber can be tuned properly within several seconds.

scholarly journals Suppression of limit cycle oscillations using the nonlinear tuned vibration absorber

2015 ◽  
Vol 471 (2176) ◽  
pp. 20140976 ◽  
Author(s):  
G. Habib ◽  
G. Kerschen
Keyword(s):  
Limit Cycle ◽  
A Priori ◽  
Numerical Continuation ◽  
Vibration Absorber ◽  
Primary System ◽  
Mathematical Form ◽  
Limit Cycle Oscillations ◽  
Van Der Pol ◽  
Restoring Force ◽  
Tuned Vibration Absorber

The objective of this study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA). An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is not imposed a priori, as it is the case for most existing nonlinear absorbers. The NLTVA parameters are determined analytically using stability and bifurcation analyses, and the resulting design is validated using numerical continuation. The proposed developments are illustrated using a Van der Pol–Duffing primary system.

Dynamic Analysis of Active Vibration Absorber by Time Delay Acceleration Feedback Using Higher Order Method of Multiple Scales

2017 ◽  
Author(s):  
S. Mohanty ◽  
S. K. Dwivedy
Keyword(s):  
Time Delay ◽  
Lead Zirconate Titanate ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Vibration Absorber ◽  
Primary System ◽  
Order Method ◽  
Primary Mass ◽  
Acceleration Feedback ◽  
Active Vibration

In the present work, analysis of a nonlinear active vibration absorber is carried out by time delay acceleration feedback. The primary system consisting of spring, mass and damper is subjected to multi harmonic and parametric excitation. It is proposed to reduce the vibration of both the primary system and the absorber by attaching a lead zirconate titanate (PZT) stack actuator connected in series with a spring in absorber configuration which act as an active vibration absorber. Due to the external excitation on the primary mass strain is developed in the PZT sensor, which produces voltage and this voltage converted to a counter acting force by the PZT actuator to suppress the vibration of the primary system. Second order method of multiple scales (MMS) is used to obtain approximate solution of the system to study frequency responses for simultaneous primary resonance, principal parametric and 1:1 internal resonance conditions. The analysis is performed for the mass ratio of 0.01 between the absorber and the primary mass.

scholarly journals Research on vibration reduction performance of dynamic vibration absorber based on damping characteristic of a new material

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402096159
Author(s):  
Weizhi Song ◽  
Zhien Liu ◽  
Chihua Lu ◽  
Yongchao Li ◽  
Bin Li
Keyword(s):  
Frequency Band ◽  
Vibration Reduction ◽  
Excitation Frequency ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Controlled System ◽  
Resonance Point ◽  
Dynamic Vibration ◽  
New Material ◽  
Active Vibration

The absorbing effect of traditional dynamic vibration absorber (TDVA) is satisfactory only when the natural frequency is close to the excitation frequency. For this defect, a semi-active vibration absorber is designed with magnetorheological elastomer (MRE) as a stiffness element, that its stiffness can be controlled by magnetic field, to widen the frequency band of the absorber. Theory and experiments show that reducing the damp of the absorber can improve the performance of the absorber at the anti-resonance point, but it will cause the vibration of the controlled system at the new resonance point, which caused by the addition of a DVA, to be more intense. For this problem, the compatibilizer: silane coupling agent KH570, is added to the preparation of MRE to reduce material damping, at the same time, the stiffness control strategy is used to eliminate the resonance of the controlled system caused by the addition of DVA. The final experimental results show that the frequency band of vibration reduction has been broadened effectively and the vibration reduction performance has been improved considerably. Moreover, the resonance has been eliminated very well.

Effects of nonlinear interactions of flexural modes on the performance of a beam autoparametric vibration absorber

2019 ◽  
Vol 26 (7-8) ◽  
pp. 459-474
Author(s):  
Saeed Mahmoudkhani ◽  
Hodjat Soleymani Meymand
Keyword(s):  
Frequency Response ◽  
Internal Resonance ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Primary System ◽  
Lumped Mass ◽  
Response Curves ◽  
Internal Resonances ◽  
The One

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

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