Tonal Tuning of a Variable Inertia Vibration Absorber: A Feasibility Study

2003 ◽  
Author(s):  
Behrooz Fallahi ◽  
Said Megahed ◽  
Mohammed Seif
Keyword(s):  
Differential Equation ◽  
Steady State ◽  
Nonlinear Model ◽  
Dynamic Equations ◽  
Vibration Absorber ◽  
Primary System ◽  
Moving Mass ◽  
New Class ◽  
Linearized Model ◽  
Tuned Vibration Absorber

The primary goal of this study is to investigate the dynamics of a new class of adaptive Tuned Vibration Absorber (TVA): A variable effective inertia absorber. In particular, the accuracy of linearization of the dynamic equations, the effect of the moving mass on the dynamics of the absorber, and steady state vibration of the primary system are investigated. It is shown that the linearized model is accurate. Two simulations using the nonlinear model are reported. These simulations show effectiveness of the absorber on reducing the displacement and acceleration of the primary system. In a third simulation, the block is moved from a detuned position to a tuned position and nonlinear differential equation of the motion is solved. The results show a significant decrease of the vibration of the primary system.

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.

Control of a Tuned Vibration Absorber Based on SMA Wires

2005 ◽  
Author(s):  
Eric Williams ◽  
Mohammad H. Elahinia ◽  
Jeong-Hoi Koo
Keyword(s):  
Shape Memory ◽  
Natural Frequency ◽  
Constitutive Relations ◽  
Robustness Analysis ◽  
Vibration Absorber ◽  
Primary System ◽  
Frequency Change ◽  
Simulation Results ◽  
Close Loop Control ◽  
Tuned Vibration Absorber

This paper presents the control simulation results of a tuned vibration absorber (TVA) that utilizes the properties of shape memory alloy (SMA) wires. A conventional passive TVA is effective when it is precisely tuned to the frequency of a vibration mode; otherwise, resonance may occur that could damage the system. Additionally, in many applications the frequency of the primary system often changes over time. For example, the mass of the primary system can change causing a change in its natural frequency. This frequency change of the primary system can significantly degrade the performance of the TVA. To cope with this problem, many alternative TVA’s (such as semiactive, adaptive, and active TVA’s) have been studied. As another alternative, this paper investigates the use of Shape Memory Alloys (SMA’s) in passive TVA’s in order to improve the robustness of the TVA’s subject to mass change in the primary system. This allows for effective tuning of the stiffness of the TVA to adapt to the changes in the primary system’s natural frequency. To this end, a close-loop control system adjusts the applied current to the SMA wires in order to maintain the desired stiffness. The model, presented in this paper, contains the dynamics of the TVA along with the SMA wire model that includes phase transformation, heat transfer, and the constitutive relations. The closed-loop robustness analysis is performed for the SMA-TVA and is compared with the equivalent passive TVA. For the robustness analysis, the mass of the primary system is varied by ± 30% of its nominal mass. The simulation results show that the SMA-TVA is more robust than the equivalent passive TVA in reducing peak vibrations in the primary system subject to change of its mass.

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.

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.

scholarly journals Dynamical Behavior of a Pseudoelastic Vibration Absorber Using Shape Memory Alloys

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Hugo De S. Oliveira ◽  
Aline S. De Paula ◽  
Marcelo A. Savi
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Dynamical Behavior ◽  
Vibration Reduction ◽  
Hysteretic Behavior ◽  
System Response ◽  
Vibration Absorber ◽  
Primary System ◽  
Secondary System ◽  
Tuned Vibration Absorber

The tuned vibration absorber (TVA) provides vibration reduction of a primary system subjected to external excitation. The idea is to increase the number of system degrees of freedom connecting a secondary system to the primary system. This procedure promotes vibration reduction at its design forcing frequency but two new resonance peaks appear introducing critical behaviors that must be avoided. The use of shape memory alloys (SMAs) can improve the performance of the classical TVA establishing an adaptive TVA (ATVA). This paper deals with the nonlinear dynamics of a passive pseudoelastic tuned vibration absorber with an SMA element. In this regard, a single degree of freedom elastic oscillator is used to represent the primary system, while an extra oscillator with an SMA element represents the secondary system. Temperature dependent behavior of the system allows one to change the system response avoiding undesirable responses. Nevertheless, hysteretic behavior introduces complex characteristics to the system dynamics. The influence of the hysteretic behavior due to stress-induced phase transformation is investigated. The ATVA performance is evaluated by analyzing primary system maximum vibration amplitudes for different forcing amplitudes and frequencies. Numerical simulations establish comparisons of the ATVA results with those obtained from the classical TVA. A parametric study is developed showing the best performance conditions and this information can be useful for design purposes.

scholarly journals Impulsive vibration mitigation through a nonlinear tuned vibration absorber

2019 ◽  
Vol 98 (3) ◽  
pp. 2115-2130 ◽  
Author(s):  
Giuseppe Habib ◽  
Fanni Kádár ◽  
Bálint Papp
Keyword(s):  
Invariant Manifolds ◽  
Initial Conditions ◽  
Mechanical Energy ◽  
Free Vibrations ◽  
Vibration Absorber ◽  
Primary System ◽  
Dynamic Vibration Absorber ◽  
Vibration Mitigation ◽  
Host Structure ◽  
Tuned Vibration Absorber

Abstract The dynamics of a nonlinear passive vibration absorber conceived to mitigate vibrations of a nonlinear host structure is considered in this paper. The system under study is composed of a primary system, consisting of an undamped nonlinear oscillator of Duffing type, and a nonlinear dynamic vibration absorber, denominated nonlinear tuned vibration absorber (NLTVA). The NLTVA consists of a small mass, attached to the host structure through a linear damper, a linear and a cubic spring. The host structure is subject to free vibrations and the performance of the NLTVA is evaluated with respect to the minimal time required to dissipate a specific amount of the mechanical energy of the system. In order to characterize the dynamics of the system, a combination of numerical and analytical techniques is implemented. In particular, on the basis of the first-order reduced model, slow invariant manifolds of the transient dynamics are identified, which enable to estimate the absorber performance. Results illustrate that two different dynamical paths exist and the system can undergo either of them, depending on the initial conditions and on the value of the absorber nonlinear stiffness coefficient. One path leads to a very fast vibration mitigation, and therefore to a favorable behavior, while the other one causes a very slow energy dissipation.

Stability Analysis of a Shape Memory Alloy Adaptive Tuned Vibration Absorber Under PI Control With Anti-Windup

2001 ◽  
Author(s):  
Keith A. Williams ◽  
George Chiu ◽  
Robert Bernhard
Keyword(s):  
Stability Analysis ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Algorithm ◽  
Relative Phase ◽  
Vibration Absorber ◽  
Primary System ◽  
Structural Elements ◽  
Integral Control ◽  
Tuned Vibration Absorber

Abstract This paper presents a stability analysis of a continuously controlled adaptive tuned vibration absorber (ATVA) incorporating shape memory alloy (SMA) structural elements to realize attenuation of the vibration of a primary system subject to uncertain tonal excitation. The objective is for the SMA ATVA stiffness to be adapted such that a relative phase angle of −90° is achieved between the vibration of the SMA ATVA and the primary mass. The Lyapunov-based stability analysis indicates that the system is stable under proportional-plus-integral control across the operating range of the SMA ATVA when an integral reset is included in the control algorithm. The integral reset also substantially improves the performance of the system when compared to the original PI controller without reset.

scholarly journals Stability area of a synchronous generator nonlinear model with multiparametric excitation controller

2021 ◽  
pp. 51-61
Author(s):  
Alexander Chekhonadskikh ◽  
Keyword(s):  
Steady State ◽  
Nonlinear Model ◽  
Numerical Experiments ◽  
Initial Perturbation ◽  
Synchronous Generator ◽  
Main Attention ◽  
Lower Amplitude ◽  
The Stability ◽  
Linearized Model ◽  
Stability Area

We take as the research object the well-known system of nonlinear differential and functional equations that describes a synchronous generator. PIDD2-control was carried out through the excitation block. Effective values of the steady state in relative units and the preliminary settings of suboptimal controllers were obtained earlier using a linearized model. Disturbing surges (spikes and slump) in bus voltages were modeled as line impedance changes. The system stabilization was studied at various surges values and controller parameters by means series of numerical experiments; the calculations were carried out by the methods of Runge-Kutta and Dorman-Prince. The main attention was paid to various transient types, both stabilizing and diverging, as well as a configuration of the stability region boundary in the controller parameters of and a surge magnitude; the paper presents the results for the proportional control parameter are as the most informative. We've identified five types of transients and several important features of the model's behavior near the stabilization area boundary. Thus, the nonlinear model turned out to be unstable to small and stable to bigger perturbations in the unstable area of its linearization. The steady-state oscillations at the boundary have a lower amplitude with increasing of an initial perturbation, etc.

Design and Test of an Adaptive Tuned Vibration Absorber for Reducing Cryogenic Cooler Vibrations

2011 ◽  
Author(s):  
Robert Sinko ◽  
Michael Karnes ◽  
Jeong-Hoi Koo ◽  
Young-Keun Kim ◽  
Kyung-Soo Kim
Keyword(s):  
Permanent Magnets ◽  
Magnetic System ◽  
Dynamic Performance ◽  
Vibration Absorber ◽  
Primary System ◽  
Design Constraints ◽  
Magnetorheological Elastomers ◽  
Cryogenic Cooler ◽  
Tuned Vibration Absorber ◽  
Two Degree Of Freedom

The focuses of this study are to design an adaptive tuned vibration absorber based on a smart material known as magnetorheological elastomers (MRE) and to test its dynamic performance. A primary system replicating a cryogenic cooler was designed and fabricated in order to test the effectiveness of the vibration absorber. A hybrid magnetic system (electromagnet and permanent magnets) was also designed and fabricated in order to actuate the MRE as an adaptive stiffness element in the vibration absorber. Vibration testing was conducted on both the primary system and vibration absorber individually in order to characterize the behavior and verify the design constraints. Further testing was performed on the two degree of freedom system to measure and assess the feasibility of the MRE material for use in an application requiring an adaptive vibration absorber. The results show that by using a hybrid design for the electromagnet within the vibration absorber, the stiffness of the MRE material can be both increased and decreased above its nominal value; therefore demonstrating the feasibility of this design as an alternative adaptive vibration absorber.

Resonance reduction of primary system using variable mass tuned vibration absorber

2014 ◽  
Vol 62 (3) ◽  
pp. 138-144 ◽  
Author(s):  
Qiang Gao ◽  
Changdong Duan ◽  
Xingbo Fang ◽  
Yanqing Zhao
Keyword(s):  
Variable Mass ◽  
Vibration Absorber ◽  
Primary System ◽  
Tuned Vibration Absorber
Sign in / Sign up

Export Citation Format

Share Document