Recent Studies of Adaptive Tuned Vibration Absorbers/Neutralizers

2009 ◽  
Vol 62 (6) ◽  
Author(s):  
Lari Kela ◽  
Pekka Vähäoja
Keyword(s):  
Piezoelectric Materials ◽  
Helmholtz Resonator ◽  
Primary System ◽  
Vibration Absorbers ◽  
Review Section ◽  
Helmholtz Resonators ◽  
Tuned Vibration Absorbers ◽  
Current Events ◽  
Year 2000 ◽  
Tuned Vibration Absorber

This article gathers together the most recent articles of adjustable tuned vibration absorbers. The tuned vibration absorber was invented over 100 years ago, and its adjustability is also already well-known. However, concentration of this review was only on articles published since the year 2000 in peer reviewed journals, except from certain elementary books and some previous review articles in order to keep up with the current events in this broad field. First a brief inspection of the theory of tuned vibration absorbers (TVAs) is presented. After that mechanical TVAs are presented more carefully. In the same chapter the following are also handled: virtual absorbers, absorbers with adjustable damping, and Helmholtz resonators. Own chapter is allocated for multiple TVAs whose idea is to replace adjustability by adding several TVAs to primary system to damp out vibrations in the wide frequency band. The review section is completed by presenting smart material TVAs, which include, e.g., piezoelectric materials, shape-memory alloys, electrorheological and magnetorheological materials of fluids. An adjustable Helmholtz resonator in a low pressure hydraulic system is presented in Sec. 5. Experiments verify the efficiency of the damping character of the adjustable Helmholtz resonator whose resonant frequency can be varied.

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.

scholarly journals Seismic Energy Assessment of Buildings with Tuned Vibration Absorbers

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Said Elias
Keyword(s):  
Integration Method ◽  
Seismic Analysis ◽  
Equations Of Motion ◽  
Seismic Energy ◽  
Vibration Absorbers ◽  
Governing Equations ◽  
Energy Assessment ◽  
Tuned Vibration Absorbers ◽  
Reduced Space ◽  
Tuned Vibration Absorber

Seismic analysis and energy assessment of building installed with distributed tuned vibration absorbers (d-TVAs) are presented. The performance of d-TVAs is compared with single tuned vibration absorber (STVA) installed at the top of the building. The placements of the d-TVAs are based on the modal properties of the uncontrolled and controlled buildings. The governing equations of motion of the building with the STVA and d-TVAs are solved by employing Newmark’s integration method. Various energies under earthquake ground excitations are computed to study the effectiveness of using the STVA and d-TVAs. It is concluded that the use of the d-TVAs is the most competent because it effectively dissipates the seismic energy, and they are convenient to install requiring reduced space, as are placed at various floors.

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.

scholarly journals A Principle of Similarity for Nonlinear Vibration Absorbers

2015 ◽  
Author(s):  
Giuseppe Habib ◽  
Gaetan Kerschen
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Vibration Absorbers ◽  
Engineering Systems ◽  
Restoring Force ◽  
Optimal Value ◽  
Real World Applications ◽  
Nonlinear Components ◽  
Principle Of Similarity ◽  
Tuned Vibration Absorber

With continual interest in expanding the performance envelope of engineering systems, nonlinear components are increasingly utilized in real-world applications. This causes the failure of well-established techniques to mitigate resonant vibrations. In particular, this holds for the linear tuned vibration absorber (LTVA), which requires an accurate tuning of its natural frequency to the resonant vibration frequency of interest. This is why the nonlinear tuned vibration absorber (NLTVA), the nonlinear counterpart of the LTVA, has been recently developed. An unconventional aspect of this absorber is that its restoring force is tailored according to the nonlinear restoring force of the primary system. This allows the NLTVA to extend the so-called Den Hartog’s equal-peak rule to the nonlinear range. In this work, a fully analytical procedure, exploiting harmonic balance and perturbation techniques, is developed to define the optimal value of the nonlinear terms of the NLTVA. The developments are such that they can deal with any polynomial nonlinearity in the host structure. Another interesting feature of the NLTVA, discussed in the paper, is that nonlinear terms of different orders do not interact with each other in first approximation, thus they can be treated separately. Numerical results obtained through the shooting method coupled with pseudo-arclength continuation validate the analytical developments.

VIBRATIONAL ENERGIES OF MEMBERS IN STRUCTURAL NETWORKS FITTED WITH TUNED VIBRATION ABSORBERS

2006 ◽  
Vol 06 (02) ◽  
pp. 269-284 ◽  
Author(s):  
SUNNY K. GEORGE ◽  
K. SHANKAR
Keyword(s):  
Energy Level ◽  
Vibrational Energy ◽  
General Structure ◽  
Energy Levels ◽  
Complex Structure ◽  
Input Power ◽  
Vibration Absorbers ◽  
Tuned Vibration Absorbers ◽  
Vibrational Energies ◽  
Structural Networks

The distribution of vibrational energy in members of a complex structure with tuned absorbers attached at the joints and subjected to dynamic loading is studied. The concept of power flows through the structure is used to determine the time-averaged energy levels of each member in the structure. The power flows are calculated using the time-averaged product of force and velocity at the input and coupling points (joints) of a general structure made of axially vibrating rods. The receptance approach is used to calculate the coupling forces and velocities in the structure. By balancing the input power against the dissipated powers, the time-averaged energy levels in members are determined. The main criteria studied here is the reduction in the frequency-averaged vibrational energy level of a member when an absorber is attached, expressed as a percentage compared to the case where there are no absorbers. The concept is first illustrated with a simple model of 2 axially vibrating rods with an absorber attached to the joint. Next, a more complex structure comprising 8 rods with arbitrary orientations and several absorbers attached to junctions is studied. The effect of activating absorbers at various locations on reducing the energy levels of certain members is examined. It is possible to estimate the usefulness of the absorber with respect to any member by determining the percentage reduction of energy level for that member.

Optimal Design of Vibration Absorber Systems Supported by Elastic Base

1991 ◽  
Author(s):  
Hashem Ashrafiuon
Keyword(s):  
Dynamic Models ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Elastic Base ◽  
Design Parameters ◽  
Primary System ◽  
Vibration Absorbers ◽  
Equivalent Damping ◽  
System Equations ◽  
Different Levels

Abstract This paper presents the effect of foundation flexibility on the optimum design of vibration absorbers. Flexibility of the base is incorporated into the absorber system equations of motion through an equivalent damping ratio and stiffness value in the direction of motion at the connection point. The optimum values of the uncoupled natural frequency and damping ratio of the absorber are determined over a range of excitation frequencies and the primary system damping ratio. The design parameters are computed and compared for the rigid, static, and dynamic models of the base as well as different levels of base flexibility.

The Influence Region Analysis for the Delayed Resonator Vibration Absorber

2001 ◽  
Author(s):  
Giulio Grillo ◽  
Nejat Olgac
Keyword(s):  
Vibration Suppression ◽  
Vibration Absorber ◽  
Primary System ◽  
Frequency Interval ◽  
Vibration Absorption ◽  
Region Analysis ◽  
The Common ◽  
Resonator Vibration ◽  
Three Degree Of Freedom ◽  
Tuned Vibration Absorber

Abstract This paper presents an influence region analysis for an actively tuned vibration absorber, the Delayed Resonator (DR). DR is shown to respond to tonal excitations with time varying frequencies [1–3]. The vibration suppression is most effective at the point of attachment of the absorber to the primary structure. In this study we show that proper feedback control on the absorber can yield successful vibration suppression at points away from this point of attachment. The form and the size of such “influence region” strongly depend on the structural properties of the absorber and the primary system. There are a number of questions addressed in this paper: a) Stability of vibration absorption, considering that a single absorber is used to suppress oscillations at different locations. b) Possible common operating frequency intervals in which the suppression can be switched from one point on the structure to the others. A three-degree-of-freedom system is taken for as example case. One single DR absorber is demonstrated to suppress the oscillations at one of the three masses at a given time. Instead of an “influence region” a set of “influence points” is introduced. An analysis method is presented to find the common frequency interval in which the DR absorber operates at all three influence points.

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