Vibration absorption of parallel-coupled nonlinear energy sink under shock and harmonic excitations

AbstractNonlinear energy sink (NES) can passively absorb broadband energy from primary oscillators. Proper multiple NESs connected in parallel exhibit superior performance to single-degree-of-freedom (SDOF) NESs. In this work, a linear coupling spring is installed between two parallel NESs so as to expand the application scope of such vibration absorbers. The vibration absorption of the parallel and parallel-coupled NESs and the system response induced by the coupling spring are studied. The results show that the responses of the system exhibit a significant difference when the heavier cubic oscillators in the NESs have lower stiffness and the lighter cubic oscillators have higher stiffness. Moreover, the e±ciency of the parallel-coupled NES is higher for medium shocks but lower for small and large shocks than that of the parallel NESs. The parallel-coupled NES also shows superior performance for medium harmonic excitations until higher response branches are induced. The performance of the parallel-coupled NES and the SDOF NES is compared. It is found that, regardless of the chosen SDOF NES parameters, the performance of the parallel-coupled NES is similar or superior to that of the SDOF NES in the entire force range.

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Reliability analysis of the hysteretic nonlinear energy sink in shock mitigation considering uncertainties

Journal of Vibration and Control ◽

10.1177/1077546320919304 ◽

2020 ◽

Vol 26 (23-24) ◽

pp. 2261-2273 ◽

Cited By ~ 1

Author(s):

George C Tsiatas ◽

Dimitra A Karatzia

Keyword(s):

Reliability Analysis ◽

Nonlinear Energy Sink ◽

System Response ◽

Primary System ◽

Dissipation Energy ◽

Linear Elastic ◽

Shock Mitigation ◽

Energy Sink ◽

Elastic Spring ◽

Nonlinear Energy

The reliability of the hysteretic nonlinear energy sink in shock mitigation is investigated herein. The hysteretic nonlinear energy sink is a passive vibration control device which is coupled to a primary linear oscillator. Apart from its small mass and a nonlinear elastic spring of the Duffing oscillator, it also comprises a purely hysteretic and a linear elastic spring of potentially negative stiffness. The Bouc–Wen model is used to describe the force produced by both the purely hysteretic and linear elastic springs. The hysteretic nonlinear energy sink protects the primary system through the energy pumping mechanism which transfers energy from the primary system and dissipates it in the hysteretic nonlinear energy sink. Three nonlinear equations of motion describe the resulting two-degree-of-freedom system response. The parameters of the system to be considered as uncertain are the natural frequency of the primary system and the hysteretic nonlinear energy sink linear elastic spring, which follow a normal distribution. A reliability analysis is then performed to evaluate the robustness of the coupled system in the presence of uncertainty. Specifically, the reliability index is calculated based on first passage probabilities of distinct dissipation energy level crossings using the Monte Carlo method. Several examples are examined considering various levels of initial input energy, and useful conclusions are drawn concerning the influence of uncertainty in the system robustness.

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A Fractional Calculus for Nonlinear Energy Sink Used in Vibration Absorption System

Noise & Vibration Worldwide ◽

10.1260/0957-4565.42.10.62 ◽

2011 ◽

Vol 42 (10) ◽

pp. 62-67

Author(s):

Song Li ◽

Bo Fang ◽

Tianzhi Yang ◽

Wenhu Huang

Keyword(s):

Fractional Calculus ◽

Nonlinear Energy Sink ◽

Small Mass ◽

Degree Of Freedom ◽

Linear Oscillator ◽

Order System ◽

Good Correspondence ◽

Vibration Absorption ◽

Energy Sink ◽

Nonlinear Energy

The phenomenon of energy pumping, in which vibratory energy is transferred irreversibly within a nonlinear, multi-degree-of-freedom system with the goal of reducing the transient response of the primary substructure, has recently been investigated analytically and through numerical simulations. The dynamics of single degree of freedom linear subsystem with attached nonlinear energy sink is investigated. The response of a linear oscillator attached to nonlinear energy sink with relatively small mass under external forcing in a vicinity of main resonance is studied analytically and numerically. It is possible that targeted energy could transfer from linear oscillators to the nonlinear energy sink in this system. Analytical model is verified numerically and a fairly good correspondence is observed. Fractional calculus offers a powerful tool to describe the dynamic behavior of real vibration absorption. A version of the fractional derivative models is presented and investigated in this paper for analyzing vibration absorption behavior of nonlinear energy sink. It is shown that the fractional-order system is in a stronger position than the traditional nonlinear energy sink coupled to the linear oscillator.

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Vibration absorption in systems with a nonlinear energy sink: Nonlinear damping

Journal of Sound and Vibration ◽

10.1016/j.jsv.2009.02.052 ◽

2009 ◽

Vol 324 (3-5) ◽

pp. 916-939 ◽

Cited By ~ 112

Author(s):

Y. Starosvetsky ◽

O.V. Gendelman

Keyword(s):

Nonlinear Energy Sink ◽

Nonlinear Damping ◽

Vibration Absorption ◽

Energy Sink ◽

Nonlinear Energy

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Thermal Effect on Dynamics of Beam with Variable-Stiffness Nonlinear Energy Sink

International Journal of Nonlinear Sciences and Numerical Simulation ◽

10.1515/ijnsns-2017-0248 ◽

2020 ◽

Vol 21 (1) ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

J. E. Chen ◽

W. Zhang ◽

M. H. Yao ◽

J. Liu ◽

M. Sun

Keyword(s):

Variable Stiffness ◽

Nonlinear Energy Sink ◽

Excitation Amplitude ◽

Harmonic Excitation ◽

Absorption Efficiency ◽

Nonlinear Stiffness ◽

Vibration Absorption ◽

Low Stiffness ◽

Energy Sink ◽

Nonlinear Energy

AbstractIn this study, we investigate the targeted energy transfer (TET) from a simply supported beam that is subjected to thermal variations and external excitations to a local nonlinear energy sink (NES). We derive the governing equation of motion for the beam with an NES device and study the influences of NES parameters on the vibration-suppressing effect. We obtain the optimized parameters of the NES under constant-amplitude harmonic excitation at room temperature. The optimized NES gradually loses its vibration absorption efficiency as the excitation amplitude and temperature increase. We change the nonlinear stiffness of the NES to mitigate the influence of temperature variation and show that NES efficiency can be enhanced by reducing the nonlinear stiffness. We propose a variable-stiffness NES, and the results demonstrate this NES is best for maintaining efficiency over the whole temperature range. We also analyze the transient responses of the system under impulse loads. Results indicate that, like the performance of the system subjected to harmonic excitation, an NES with relatively low stiffness can better suppress vibration with increasing impulse amplitude and temperature.

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Optimal Semiactive Damping Control for a Nonlinear Energy Sink Used to Stabilize Milling

Shock and Vibration ◽

10.1155/2020/8837753 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Zhuo Chen ◽

Huancai Lu

Keyword(s):

Cutting Force ◽

Primary Structure ◽

Nonlinear Energy Sink ◽

Vibration Absorber ◽

Semiactive Control ◽

Vibration Absorbers ◽

Control Methods ◽

Damping Control ◽

Energy Sink ◽

Nonlinear Energy

Improving product quality of machining components has always met with problems due to the vibration of the milling machine’s spindle, which can be reduced by adding a vibration absorber. The tuned vibration absorber (TVA) has been studied extensively and found to have a narrow bandwidth, but the cutting force possesses wide bandwidth in the process of machining parts. Introducing nonlinearity into the dynamic vibration absorber can effectively increase the bandwidth of vibration suppression and can significantly improve the robustness of the vibration absorber. In addition, a semiactive TVA has proved to be more effective than a passive TVA for many applications, so the main purpose of this study is to find some appropriate semiactive control methods for a nonlinear energy sink (NES), a nonlinear vibration absorber, in structural vibration applications. Two semiactive control methods are considered in this study: continuous groundhook damping control based on velocity and on-off groundhook damping control based on velocity. To fairly compare these vibration absorbers, the optimal parameters of a passive TVA, a passive NES, and two semiactive NESs are designed using numerical optimization techniques to minimize the root-mean-square acceleration. Two cutting forces are introduced in this study, a periodic force and an aperiodic force, and the four vibration absorbers are compared. When the primary structure is excited with aperiodic cutting force, the amplitude of the primary structure decreased by 17.73% with the passive TVA, by 72.29% with the passive NES, by 73.54% with the on-off NES, and by 87.54% with the continuous NES. When the primary structure is excited with periodic cutting force, the amplitude of the primary structure decreased by 49.01% with a passive TVA, by 86.93% with a passive NES, by 96.38% with an on-off NES, and by 99.23% with a continuous NES. The results show that the passive NES is better than the passive TVA; the semiactive NES provides more effective vibration attenuation than the passive NES, and the continuous control is more effective than the on-off control.

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