scholarly journals Some Recent Developments in Adaptive Tuned Vibration Absorbers/Neutralisers

2006 ◽  
Vol 13 (4-5) ◽  
pp. 531-543 ◽  
Author(s):  
Michael J. Brennan
Keyword(s):  
Vibration Control ◽  
Narrow Band ◽  
Notch Filter ◽  
Variable Stiffness ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
The Past ◽  
Tuned Vibration Absorbers ◽  
Control Scheme ◽  
Recent Developments

The vibration absorber has been used for vibration control purposes in many sectors of engineering from aerospace, to automotive to civil, for the past 100 years or so. A limitation of the device, however, is that it acts like a notch filter, only being effective over a narrow band of frequencies. Recent developments have overcome this limitation by making it possible to tune the device over a range of frequencies. This has been achieved by incorporating a variable stiffness element that can be adjusted in real-time. In this paper, some ways in which stiffness change can be achieved in practice are reviewed and some examples of prototype adaptive tuned vibration absorbers (ATVAs) are described. A simple control scheme to automatically tune an ATVA is also presented.

Implementation of Tuned Vibration Absorbers for Above Ground Pipeline Vibration Control

2000 ◽  
Author(s):  
Mark A. Norris ◽  
Keith R. Ptak ◽  
Ben A. Zamora ◽  
James D. Hart
Keyword(s):  
Vibration Control ◽  
Vibration Suppression ◽  
The Arctic ◽  
Vibration Absorbers ◽  
Recent Application ◽  
Optimal Tuning ◽  
Tuned Vibration Absorbers ◽  
Recent Developments ◽  
Environmental Considerations ◽  
Pipeline Vibration

An overview of recent developments of tuned vibration absorbers (TVAs) for vibration suppression is presented. The paper summarizes some popular theory for analysis and optimal tuning of these devices, discusses various design configurations, and reviews the recent application of TVAs to control wind-induced oscillations of pipelines above the Arctic Circle. Although the wind-induced pipeline vibrations are relatively small, the accumulation of vibration cycles can cause fatigue at pipeline joints. The TVAs used in this application have reduced the RMS displacements of the pipeline by as much as a factor of seven. Additionally, the paper introduces a new overhead TVA installation on the pipeline for accommodating environmental considerations.

Designs for an adaptive tuned vibration absorber with variable shape stiffness element

2005 ◽  
Vol 461 (2064) ◽  
pp. 3955-3976 ◽  
Author(s):  
Philip Bonello ◽  
Michael J Brennan ◽  
Stephen J Elliott ◽  
Julian F.V Vincent ◽  
George Jeronimidis
Keyword(s):  
Vibration Control ◽  
Shape Change ◽  
Excitation Frequency ◽  
Variable Stiffness ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Time Varying ◽  
Variable Geometry ◽  
Curved Beams ◽  
Tuned Vibration Absorber

An adaptive tuned vibration absorber (ATVA) with a smart variable stiffness element is capable of retuning itself in response to a time-varying excitation frequency, enabling effective vibration control over a range of frequencies. This paper discusses novel methods of achieving variable stiffness in an ATVA by changing shape, as inspired by biological paradigms. It is shown that considerable variation in the tuned frequency can be achieved by actuating a shape change, provided that this is within the limits of the actuator. A feasible design for such an ATVA is one in which the device offers low resistance to the required shape change actuation while not being restricted to low values of the effective stiffness of the vibration absorber. Three such original designs are identified: (i) A pinned–pinned arch beam with fixed profile of slight curvature and variable preload through an adjustable natural curvature; (ii) a vibration absorber with a stiffness element formed from parallel curved beams of adjustable curvature vibrating longitudinally; (iii) a vibration absorber with a variable geometry linkage as stiffness element. The experimental results from demonstrators based on two of these designs show good correlation with the theory.

Experimental Vibration Control of a Two-Degree of Freedom, State-Switched Absorber System

2002 ◽  
Author(s):  
Mark H. Holdhusen ◽  
Kenneth A. Cunefare
Keyword(s):  
Vibration Control ◽  
Vibration Suppression ◽  
Effective Bandwidth ◽  
Vibration Absorbers ◽  
Lumped Mass ◽  
Tuned Vibration Absorbers ◽  
Resonance Frequencies ◽  
Magneto Rheological ◽  
Theoretical Simulations ◽  
Two Degree Of Freedom

A State-Switched Absorber (SSA) is a device capable of instantaneously changing its stiffness, thus it can switch between resonance frequencies, increasing its effective bandwidth as compared to classical tuned vibration absorbers for vibration control. Previous theoretical simulations show that for a system subjected to a multi-harmonic disturbance, using an appropriate logic for switching states, the SSA reduces vibration more effectively than classical tuned vibration absorbers (TVA). This paper considers the experimental performance of the SSA for vibration suppression of an elastically mounted lumped mass base. State switching is achieved using magneto-rheological fluid to connect or disconnect a coil spring in parallel with other coil springs. The stiffness state is controlled by applying or removing a magnetic field across of the MR fluid. Experiments were performed over a range of forcing and tuning frequencies. The SSA system, optimally tuned, outperformed the optimal classical TVA system for all combinations of forcing frequencies.

scholarly journals Homopolymer Based Magnetorheological Elastomer

2021 ◽  
pp. 54-57
Author(s):  
Parth Dhrangdhariya ◽  
Sunil Padhiyar ◽  
Prince Mishra
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Vibration Control ◽  
Applied Magnetic Field ◽  
Variable Stiffness ◽  
Rubber Matrix ◽  
Vibration Absorber ◽  
Vibration Isolator ◽  
Magnetorheological Elastomer ◽  
Spring Force

Magnetorheological rubber belongs to the class of ‘Smart Material’ whose mechanical properties can be altered continuously and reversibly by an applied magnetic field. Magnetorheological rubber (MRE’s) are composites that consists of magnetically polarisable particles mixed into rubber matrix. With suitable controlled algorithms, they respond to change in their environment. Purpose of this work is to know more about magnetorheological rubber for active stiffness, vibration control and dampening applications. Although few applications of these materials have been reported in the literature, the possibilities are numerous. They can be used for various applications such as vibration absorber, vibration isolator, variable stiffness bush, spring, force sensors, actuators etc.

State-Switched Absorber for Vibration Control of Point-Excited Beams

2000 ◽  
Author(s):  
Kenneth A. Cunefare
Keyword(s):  
Dynamical System ◽  
Vibration Control ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Spring Element ◽  
Current State ◽  
Resonance Frequencies ◽  
Spectral Components ◽  
Improved Performance ◽  
Force Excitation

Abstract A system that has the capability to make instantaneous changes in its mass, stiffness, or damping may be termed a state-switchable dynamical system. Such a system will display different dynamical responses dependent upon its current state. State-switchable stiffness may be practically obtained through the control of the termination impedance of piezoelectric stiffness elements. If such a switchable stiffness element is incorporated as part of the spring element of a vibration absorber, the change in stiffness causes a change in the resonance frequencies of the system, thereby instantaneously ‘retuning’ the state-switched absorber to a new frequency. In between state switches, the operation of such a device is passive, being fundamentally a passive vibration absorber. This concept has improved performance over classical passive vibration absorbers or dampers, particularly for disturbances with multiple spectral components. This paper considers the application of such a device for the purpose of vibration control on beams subjected to harmonic point-force excitation.

A Study on the Application of Tuned Vibration Absorbers to Nominally Cyclic Structures

2019 ◽  
Author(s):  
Mainak Mitra ◽  
Andrea Lupini ◽  
Bogdan I. Epureanu
Keyword(s):  
Small Mass ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Lumped Mass ◽  
Absorption Mechanism ◽  
Vibration Absorption ◽  
Tuned Vibration Absorbers ◽  
Cyclic Symmetric ◽  
Stiffness And Damping ◽  
Symmetric Structures

Abstract The vibration absorber or tuned mass damper is a well-known mechanism, where a small mass connected to a larger structure is used to redirect vibration energy and provide reduction in vibration amplitudes at desired locations and frequencies. While tuned vibration absorbers have been widely applied for damping of mechanical systems, the concept remains largely unexplored in the design of dampers for bladed disks. This paper investigates whether such a vibration absorption mechanism is feasible for such nominally cyclic symmetric structures which are characterized by double modes, high modal density, and sensitivity to uncertainties such as mistuning. The single-degree of freedom vibration absorber concept is extended for application to this complex modal space, and lumped mass models are used for analysis. Trends in effectiveness of a vibration absorption based damper are explored by studying sensitivities to various parameters such as stiffness and damping at various locations. Effects of mistuning across sectors and locations of damper attachment are also considered. The results of the study establish the feasibility of the vibration absorption mechanism for application in blisks, and encourage further exploration of the concept, possibly in conjunction with other well-established damping mechanisms such as friction.

Unknown Multiple Narrow-Band Disturbance Rejection in Hard Disk Drives: An Adaptive Notch Filter and Perfect Disturbance Observer Approach

2010 ◽  
Author(s):  
Xu Chen ◽  
Masayoshi Tomizuka
Keyword(s):  
Disturbance Observer ◽  
Narrow Band ◽  
Hard Disk Drives ◽  
Notch Filter ◽  
Hard Disk ◽  
Disk Drive ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Adaptive Notch Filter ◽  
Control Scheme

In this paper, an adaptive control scheme is developed to reject unknown multiple narrow-band disturbances in a hard disk drive. An adaptive notch filter is developed to efficiently estimate the frequencies of the disturbance. Based on the correctly estimated parameters, a disturbance observer with a newly designed multiple band-pass filter is constructed to achieve asymptotic perfect rejection of the disturbance. Evaluation of the control scheme is performed on a benchmark problem for HDD track following.

A Comprehensive Off-Tuning Analysis of Damping Controlled Tuned Vibration Absorbers

2006 ◽  
Author(s):  
Jeong-Hoi Koo ◽  
Medhi Ahmadian
Keyword(s):  
Numerical Models ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Single Degree Of Freedom ◽  
Tuning Parameters ◽  
Tuned Vibration Absorbers ◽  
Dynamic Performances ◽  
Displacement Based ◽  
Stiffness And Damping ◽  
Tuned Vibration Absorber

The main purpose of this study is to offer a comprehensive off-tuning analysis of a semi-active tuned vibration absorber. A base-excited, single-degree-of-freedom structure with a tuned vibration absorber (TVA) model is adapted as the baseline model for our analysis. Moreover, a non-model based groundhook control (displacement based on-off control or "On-off DBG") is used to control the damping in the TVA. In order to study the effect of off-tuning, numerical models of the damping controlled TVA along with its equivalent passive TVA were developed. Using these models, the optimal tuning parameters of both TVA models were obtained based on minimization of peak transmissibility. The two optimally tuned models were then "off-tuned" by varying the primary structure's mass, stiffness, and damping. Using the peak transmissibility reduction criteria, the dynamic performances of the off-tuned TVAs were evaluated. The results indicate that the peak transmissibility of the semi-active TVA is about 20% lower than that of passive, implying that the semi-active TVA is more effective in reducing vibration levels. The results further indicate that the semi-active TVA is more robust to changes in primary structure mass and stiffness. In summary, the offtuning analyses of the semi-active TVA revealed the practical benefits of using it over the passive counterpart to structures subjected to changes in system parameters.

Dual-mass flywheels with tuned vibration absorbers for application in heavy-duty truck powertrains

2020 ◽  
Vol 234 (10-11) ◽  
pp. 2500-2508 ◽  
Author(s):  
Lina Wramner
Keyword(s):  
Combustion Engine ◽  
Vibration Absorber ◽  
Torsional Vibrations ◽  
Vibration Absorbers ◽  
Heavy Duty ◽  
Heavy Duty Truck ◽  
Tuned Vibration Absorbers ◽  
Resonance Frequencies ◽  
Tuning Frequency ◽  
Tuned Vibration Absorber

As the heavy-duty combustion engine development goes towards lower rotational speeds and higher cylinder pressures, the torsional vibrations increase. There is therefore a need to identify and study new types of vibration absorbers that can reduce the level of torsional vibrations transmitted from the engine to the gearbox. In this work, the concept of a dual-mass flywheel combined with a tuned vibration absorber is analysed. The tuned vibration absorber efficiently reduces the vibration amplitudes for engine load frequencies near the tuning frequency, but it also introduces an additional resonance into the system. By placing the tuned vibration absorber on an intermediate flange between the two dual-mass flywheels, the introduced resonance frequency will be lower than the tuning frequency and a resonance in operating engine speed range can be avoided. Numerical simulations are used to show how the torsional vibration amplitudes in a heavy-duty truck powertrain are affected by the tuned vibration absorber and how the different parameters of the tuned vibration absorber and the dual-mass flywheel affect the torsional vibrations and the resonance frequencies.

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