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Showing papers on "Dynamic Vibration Absorber published in 2013"


Journal ArticleDOI
Zhongjie Li1, Lei Zuo1, George Luhrs1, Liangjun Lin1, Yi-Xian Qin1 
TL;DR: Results show that variable damping coefficients and the asymmetric feature in jounce and rebound motions are achieved by controlling the electrical load of the shock absorber.
Abstract: This paper presents the design, modeling, bench experiments, and road tests for a retrofit regenerative shock absorber based on a permanent magnetic generator and a rack-pinion mechanism for the purposes of energy harvesting and vibration damping. Results show that variable damping coefficients and the asymmetric feature in jounce and rebound motions are achieved by controlling the electrical load of the shock absorber. Improved efficiency and reliability are achieved by utilizing a roller to guide the rack and preload on the gear transmission to reduce backlash and friction. A peak power of 68 W and average power of 19 W are attained from one prototype shock absorber when the vehicle is driven at 48 km/h (30 mi/h) on a fairly smooth campus road.

304 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a micro-perforated panel absorber backed by Helmholtz resonators to improve sound absorption in the low-frequency region where conventional MPRs cannot provide sufficient absorption.

112 citations



Journal ArticleDOI
TL;DR: In this paper, a viscoelastic coupling damper (VCD) is proposed to increase the level of inherent damping of tall coupled shear wall buildings to control wind-induced and earthquake-induced dynamic vibrations.
Abstract: SUMMARY As high-rise buildings are built taller and more slender, their dynamic behavior becomes an increasingly critical design consideration. Wind-induced vibrations cause an increase in the lateral wind design loads, but more importantly, they can be perceived by building occupants, creating levels of discomfort ranging from minor annoyance to severe motion sickness. The current techniques to address wind vibration perception include stiffening the lateral load-resisting system, adding mass to the building, reducing the number of stories, or incorporating a vibration absorber at the top of the building; each solution has significant economic consequences for builders. Significant distributed damage is also expected in tall buildings under severe seismic loading, as a result of the ductile seismic design philosophy that is widely used for such structures. In this paper, the viscoelastic coupling damper (VCD) that was developed at the University of Toronto to increase the level of inherent damping of tall coupled shear wall buildings to control wind-induced and earthquake-induced dynamic vibrations is introduced. Damping is provided by incorporating VCDs in lieu of coupling beams in common structural configurations and therefore does not occupy any valuable architectural space, while mitigating building tenant vibration perception problems and reducing both the wind and earthquake responses of the structure. This paper provides an overview of this newly proposed system, its development, and its performance benefits as well as the overall seismic and wind design philosophy that it encompasses. Two tall building case studies incorporating VCDs are presented to demonstrate how the system results in more efficient designs. In the examples that are presented, the focus is on the wind and moderate earthquake responses that often govern the design of such tall slender structures while reference is made to other studies where the response of the system under severe seismic loading conditions is examined in more detail and where results from tests conducted on the viscoelastic material and the VCDs in full-scale are presented. Copyright © 2013 John Wiley & Sons, Ltd.

97 citations


Journal ArticleDOI
TL;DR: In this article, the authors analyzed the geometric filtering phenomenon with a simplified vertical vehicle model and found that geometric filtering consists of a "whole" process, where the filtering process consists of two phases.
Abstract: The geometric filtering phenomenon is first analyzed with a simplified vertical vehicle model. Analytical solutions obtained with this model show that geometric filtering phenomenon consists of ‘wh...

78 citations


Journal ArticleDOI
TL;DR: In this article, a new adaptive passive dynamic vibration absorber (DVA) design is discussed, which is composed of a string under variable tension with a central mass attachment as an undamped DVA and a negative stiffness mechanism as a string tension adjustment aid.

71 citations


Journal ArticleDOI
TL;DR: In this article, the optimal selection of the parameters of a passive dynamic vibration absorber (DVA) attached to a boring bar was focused on the optimal optimization problem. But the analysis of the stability of the system was limited to the Euler-Bernoulli cantilever beam.

61 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provided an analytical proof of the optimal tuning of CPVAs to reduce in-plane translational and rotational vibration for a rotor with N cyclically symmetric substructures attached to it.

50 citations


Journal ArticleDOI
TL;DR: In this article, a torsional adaptive tunable vibration absorber using a magnetorheological elastomer for vibration reduction of a powertrain test rig is presented, which can work in a frequency range from 10.75 to 16.5 Hz (53% relative change).
Abstract: This article presents the development of a torsional adaptive tunable vibration absorber using a magnetorheological elastomer for vibration reduction of a powertrain test rig. The magnetorheological elastomer used to develop the adaptive tunable vibration absorber consists of silicone polymer, silicone oil and magnetic particles with the weight percentages of 60%, 20% and 20%, respectively. Experimental testing is conducted to obtain the magnetorheological elastomer’s properties, such as Young’s modulus and the damping ratio, and effective formulas are derived to facilitate the design of the adaptive tunable vibration absorber. With the derived formulas, a magnetorheological elastomer–based adaptive tunable vibration absorber is designed and manufactured, and experimental testing is also conducted to validate the design. The results of experiments show that the magnetorheological elastomer–based adaptive tunable vibration absorber can work in a frequency range from 10.75 to 16.5 Hz (53% relative change). ...

47 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe the application of an on-line algebraic identification methodology for parameter and signal estimation in vibrating mechanical systems, which is used to estimate mass, stiffness, and viscous damping in simple mechanical systems using only position measurements.
Abstract: This paper describes the application of an on-line algebraic identification methodology for parameter and signal estimation in vibrating mechanical systems. An important property of the algebraic identification is that the parameter identification is not asymptotic but algebraic, that is, the parameters are computed as fast as the system dynamics are being excited by some external input or by changes in the initial conditions. The algebraic identification is then employed to estimate mass, stiffness, and viscous damping in simple mechanical systems using only position measurements. This approach is also used in the identification of frequency, phase, and amplitude of exogenous vibrations affecting a mechanical system. The algebraic identification is then combined with a certainty equivalence controller to asymptotically stabilize the system response and, simultaneously, cancel harmonic vibrations. The proposed adaptive-like control scheme is fast and robust against unknown parameters and frequency variations. Some numerical and experimental results illustrate the dynamic and robust performance of the algebraic identification and the active vibration controller.

42 citations


Journal ArticleDOI
Robert Sinko1, Michael Karnes1, Jeong-Hoi Koo1, Young Keun Kim2, Kyung-Soo Kim2 
TL;DR: In this article, an adaptive-tuned vibration absorber based on magnetorheological elastomers and a hybrid magnetic system (electromagnet and permanent magnets) was designed and fabricated in order to actuate the magnetic elastomer as an adaptive stiffness element in the vibration absorbers.
Abstract: The focuses of this study are to design an adaptive-tuned vibration absorber based on a smart materials known as magnetorheological elastomers and to test its dynamic performance. A primary system replicating a miniature cryogenic cooler (i.e. mass and shape) 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 magnetorheological elastomers as an adaptive stiffness element in the vibration absorber. The 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 a 2-degrees-of-freedom system to measure and assess the feasibility of the magnetorheological elastomer material for use in an application requiring an adaptive vibration absorber. The results show that by using a hybrid design for the electromagnet withi...

Journal ArticleDOI
TL;DR: In this paper, an electromagnetic device with an adaptive synthetic shunt impedance, which provides a controllable effective mechanical stiffness and damping is proposed and implemented digitally and can be altered in real-time to allow the system to adapt.
Abstract: Tuned vibration absorbers (TVAs) are effective devices for vibration control in the presence of tonal excitation, but when the properties of the host structure change or the excitation frequency varies they become detuned and their performance can degrade to an unacceptable level. It is therefore desirable that the properties of the TVA can adapt to maintain optimal tuning. In this paper an electromagnetic device with an adaptive synthetic shunt impedance which provides a controllable effective mechanical stiffness and damping is proposed. The shunt impedance, comprising resistance and capacitance, is implemented digitally and can be altered in real-time to allow the system to adapt. A model-based feedforward controller is designed and implemented to adapt both the shunt resistance and capacitance to ensure the tuned frequency of the vibration absorber tracks the excitation frequency. This ensures that the system has optimal performance throughout a large range of excitation frequencies. Simulations and experimental results show that the adaptive controller can successfully adapt the system to track a variable excitation frequency and hence demonstrates better performance than the equivalent non-adaptive undamped system, as well as an optimally tuned damped system. (Some figures may appear in colour only in the online journal)

Journal ArticleDOI
TL;DR: In this paper, the averaging method is used to research the approximately analytical solution of a semi-active on-off dynamic vibration absorber (DVA), and at first the analytical solution...
Abstract: In this paper the averaging method is used to research the approximately analytical solution of a semi-active on-off dynamic vibration absorber (DVA). At first the approximately analytical solution...

Journal ArticleDOI
TL;DR: In this paper, the symmetry breaking effects on the vibration mode structure of CPVA systems when multiple groups of absorbers are used were studied and the critical speeds and flutter instability of the system were investigated.

Journal ArticleDOI
TL;DR: In this article, the authors describe the development of an electromechanical mass-spring-damper which seeks to serve both goals of passive vibration control and energy harvesting, using a piezoelectric film spring and a distributed mass layer.

Journal ArticleDOI
TL;DR: In this paper, the behavior of a new type of nonlinear dynamic vibration absorber is studied, which is attached to a single degree-of-freedom linear/nonlinear oscillator subjected to a periodic external excitation.

Journal ArticleDOI
Ryan L. Harne1
TL;DR: In this paper, an analysis of distributed single and two-degree-of-freedom, linear electromagnetic oscillators attached to a harmonically excited panel is presented, and the simultaneous goals of vibration attenuation of the host panel and harvested electrical power are computed for several scenarios.

Journal ArticleDOI
TL;DR: In this paper, the authors employed modal filters for simultaneous and independent control of multiple vibration modes of a flexible structure embedded with a non-collocated pair of sensor and actuator.

Journal ArticleDOI
TL;DR: In this paper, a piezoelectric energy harvesting shock absorber (PEHSA) system for vehicles was developed to act as an energy harvester that converts vibration energy to electrical energy.
Abstract: Only ∼20% of a vehicle's fuel consumption is used for overcoming air drag force and friction with the road. Vibration energy produced during driving is dissipated by shock absorbers in the vehicle suspension. A new Piezoelectric Energy-Harvesting Shock Absorber (PEHSA) system for vehicles has been developed to act as an energy harvester that converts vibration energy to electrical energy. Cylindrical piezoelectric transducers are combined with the cylinder of the shock absorber to generate electricity from changes in fluid pressure produced by piston vibrations. A multiphysics simulation was performed using COMSOL Multiphysics to determine the characteristics of the PEHSA system.


Journal ArticleDOI
TL;DR: In this paper, the authors considered an optimization problem of another model of DVA that is called three-element type DVA for damped primary structures, which contains two spring elements in which one is connected to a dashpot in series and the other is placed in parallel, and the main idea of the study is based on the criteria of the equivalent linearization method in order to replace approximately the original damped structure by an equivalent undamped one.

Journal ArticleDOI
TL;DR: In this article, the solutions to H∞ and H2 optimization problems of a variant dynamic vibration absorber (DVA) applied to suppress vibration in beam structures are derived analytically.
Abstract: The solutions to H∞ and H2 optimization problems of a variant dynamic vibration absorber (DVA) applied to suppress vibration in beam structures are derived analytically. The H∞ optimum parameters such as tuning frequency and damping ratios are expressed based on fixed-point theory to minimize the resonant vibration amplitude, as well as, the H2 optimum parameters to minimize the total vibration energy or the mean square motion of a beam under random force excitation as analytical formulas. The reduction in maximum amplitude responses and mean square motion of a beam using the traditional vibration absorber is compared with the proposed dynamic absorber. Numerical results show the non-traditional DVA under optimum conditions has better vibration suppression performance on beam structures than the traditional design of DVA. Furthermore, comparing H∞ and H2 optimization procedures shows that for a beam under random force excitation, use of H2 optimum parameters resulting in smaller mean square motion than the other optimization.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a hybrid vibration absorber (HVA) which is optimized to suppress resonant vibration of a single degree-of-freedom (SDOF) system is re-optimized for suppressing wide frequency band vibration of the system under stationary random force excitation.

Journal ArticleDOI
TL;DR: In this paper, the performance of an oscillator consisting of mass and spring at the tip of a symmetrically cantilever composite beam is investigated under chordwise base excitation.
Abstract: Large flexible structures can be modeled as flexible beams with an appendage. Passive, semi-active or active vibration absorber can be used as an appendage in such structures. In this paper, the performance of an oscillator consisting of mass and spring at the tip of a symmetrically cantilever composite beam is investigated under chordwise base excitation. The oscillator is located at the tip of the beam in order to relate first-order uncoupled modes of the composite beam through internal resonance. Natural frequencies which are dependent on the oscillator parameters have been selected such that two-to-one and one-to-one internal resonance can be produced. The motion of the combined system is described by a set of four non-linear coupled partial differential equations, corresponding to the four describing variables of motion. The equations of motion are then solved using the method of multiple-scales in the occurrence of two-to-one and one-to-one internal resonances. Saturation phenomenon is detected in the force modulation response at the one-to-one internal resonance. Reduction of amplitudes is shown in both frequency and force–response curves under primary resonance.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the semi-active control of a magnetically-tunable vibration absorber's resonance frequency under arbitrary stress and magnetic field, and showed that nearly uniform controllability of the vibrational frequency is possible below a threshold of the input power amplitude using weak magnetic fields.
Abstract: This paper investigates the semi-active control of a magnetically-tunable vibration absorber’s resonance frequency. The vibration absorber that is considered is a metal-matrix composite containing the magnetostrictive material Galfenol (FeGa). A single degree of freedom model for the nonlinear vibration of the absorber is presented. The model is valid under arbitrary stress and magnetic field, and incorporates the variation in Galfenol’s elastic modulus throughout the composite as well as Galfenol’s asymmetric tension–compression behavior. Two boundary conditions—cantilevered and clamped–clamped—are imposed on the composite. The frequency response of the absorber to harmonic base excitation is calculated as a function of the operating conditions to determine the composite’s capacity for resonance tuning. The results show that nearly uniform controllability of the vibration absorber’s resonance frequency is possible below a threshold of the input power amplitude using weak magnetic fields of 0–8 kA m−1. Parametric studies are presented to characterize the effect on resonance tunability of Galfenol volume fraction and Galfenol location within the composite. The applicability of the results to composites of varying geometry and containing different Galfenol materials is discussed.

Journal ArticleDOI
TL;DR: In this article, the possibility of controlling two modes of structural vibration due to earthquake excitation by considering the sloshing action in the vertical limbs of the liquid column vibration absorber (LCVA) has been explored.
Abstract: The possibility of controlling two modes of structural vibration due to earthquake excitation by considering the sloshing action in the vertical limbs of the liquid column vibration absorber (LCVA) has been explored in this paper. The structure has been modeled as a linear, viscously damped multi-degree-of-freedom (m.d.f.) system. The governing differential equations of motion for the damper liquid and for the coupled structure-LCVA system have been derived from dynamic equilibrium. The nonlinear orifice damping in the LCVA has been linearized by a stochastic equivalent linearization technique. A displacement transfer function formulation for the structure-LCVA system has been presented. The study has been carried out on a 2-d.f. example structure for which both the modes have significant contribution to the total response. The performance of the LCVA has been evaluated in the frequency domain with the base input characterized by a white noise power spectral density function and through a simulation study...


Journal ArticleDOI
TL;DR: In this paper, the authors extended the concept of an energy threshold to a more general parameter threshold representing several threshold values, and generalized the results to linear main systems under impulsive load and harmonic load, nonlinear main systems, and general nonlinear spring characteristics.
Abstract: A popular means to mitigate excessive structural vibrations is the attachment of a lightweight spring-mass element, known as a vibration absorber or tuned mass damper. Designing new types of vibration absorbers that outperform the classical linear tuned mass damper is a challenging ongoing research field. This paper focuses on the absorber with a strongly nonlinear spring characteristic. A critical aspect in the design procedure of such nonlinear vibration absorber is the existence of energy thresholds below which no efficient vibration reduction is possible. This paper extends the concept of an energy threshold to a more general parameter threshold representing several threshold values. Two important contributions are obtained. First, one single bifurcation analysis covers every combination of the system parameters. Second, the results are generalized to linear main systems under impulsive load and harmonic load, nonlinear main systems, and general nonlinear spring characteristics.

Proceedings ArticleDOI
26 May 2013
TL;DR: In this article, the design of laboratory test rig of wind turbine's tower-nacelle model with horizontally aligned magnetorheological tuned vibration absorber is addressed, and several model constraints are fulfilled.
Abstract: The paper addresses the design of laboratory test rig of wind turbine's tower-nacelle model with horizontally aligned magnetorheological tuned vibration absorber. Several model constraints are fulfilled. Test rig design is featured and described. Its main elements are: vertical stiff rod (a tower) and a system of steel plates and blocks that is fitted rigidly at rod's top (a nacelle), connected horizontally via a spring and MR damper with an additional mass of vibration absorber. The nacelle is excited horizontally, forcing tower bending modes of vibration. The rod itself may be either fitted rigidly at its bottom to the ground and excited horizontally at an arbitrary height by the second shaker, or laid on the steel plate being excited horizontally.

Book ChapterDOI
11 Feb 2013
TL;DR: In this paper, the physical behavior and effectiveness of a nonlinear dynamic vibration absorber (NDVA) was investigated and compared with a linear absorber with a hardening spring attached to a cantilever beam excited by a shaker.
Abstract: This paper investigates the physical behaviour and effectiveness of a nonlinear dynamic vibration absorber (NDVA). The nonlinear absorber considered involves a nonlinear hardening spring which was designed and attached to a cantilever beam excited by a shaker. The cantilever beam can be considered at low frequencies as a linear single degree-of-freedom system. The nonlinear attachment is designed to behave as a hardening Duffing oscillator. The nonlinearity of the attachment is due to the particular geometrical configuration undergoing a large amplitude response. The experiment investigated the potential for vibration reduction of the system Analytical and numerical results are presented and compared. From the measured results it was observed that the NDVA had a much wider effective bandwidth compared to a linear absorber. The frequency response curve of the NDVA has the effect of moving the second resonant peak to a higher frequency away from the tuned frequency so that the device is robust to mistuning.