Experimental Investigation of Targeted Energy Transfers in Strongly and Nonlinearly Coupled Oscillators

Author(s):  
D. M. McFarland ◽  
G. Kerschen ◽  
J. J. Kowtko ◽  
Y. S. Lee ◽  
L. A. Bergman ◽  
...  

The focus of this study is on experimental investigation of the transient dynamics of an impulsively loaded linear oscillator coupled to a light-weight nonlinear energy sink. It is shown that this seemingly simple system exhibits complicated dynamics, including nonlinear beating phenomena and resonance captures. It is also demonstrated that, by facilitating targeted energy transfers to the nonlinear energy sink, a significant portion of the total input energy can be absorbed and dissipated in this oscillator.

2012 ◽  
Vol 69 (4) ◽  
pp. 1693-1704 ◽  
Author(s):  
G. Sigalov ◽  
O. V. Gendelman ◽  
M. A. AL-Shudeifat ◽  
L. I. Manevitch ◽  
A. F. Vakakis ◽  
...  

Author(s):  
Amir Nankali ◽  
Harsheeta Surampalli ◽  
Young S. Lee ◽  
Tama´s Kalma´r-Nagy

Suppression of regenerative instability in a single-degree-of-freedom (SDOF) machine tool model was studied by means of targeted energy transfers (TETs). The regenerative cutting force generates time-delay effects in the tool equation of motion, which retained the nonlinear terms up to the third order in this work. Then, an ungrounded nonlinear energy sink (NES) was coupled to the SDOF tool, by which biased energy transfers from the tool to the NES and efficient dissipation can be realized whenever regenerative effects invoke instability in the tool. Shifts of the stability boundary (i.e., Hopf bifurcation point) with respect to chip thickness were examined for various NES parameters. There seems to exist an optimal value of damping for a fixed mass ratio to shift the stability boundary for stably cutting more material off by increasing chip thickness; on the other hand, the larger the mass ratio becomes, the further the occurrence of Hopf bifurcation is delayed. The limit cycle oscillation (LCO) due to the regenerative instability appears as being subcritical, which can be (locally) eliminated or attenuated at a fixed rotational speed of a workpiece by the nonlinear modal interactions with an NES (i.e., by means of TETs). Three suppression mechanisms have been identified; that is, recurrent burstouts and suppressions, partial and complete suppressions of regenerative instabilities in a machine tool model. Each suppression mechanism was characterized numerically by time histories of displacements, and wavelet transforms and instantaneous energies. Furthermore, analytical study was performed by employing the complexification-averaging technique to yield a time-delayed slow-flow model. Finally, regenerative instability suppression in a more practical machine tool model was examined by considering contact-loss conditions.


2016 ◽  
Vol 10 (3) ◽  
pp. 147 ◽  
Author(s):  
Rodrigo Tumolin Rocha ◽  
Jose Manoel Balthazar ◽  
Angelo Marcelo Tusset ◽  
Vinicius Piccirillo ◽  
Jorge Luis Palacios Felix

2021 ◽  
Vol 64 (5) ◽  
Author(s):  
Nan Duan ◽  
Sida Lin ◽  
Yuhu Wu ◽  
Xi-Ming Sun ◽  
Chongquan Zhong

2021 ◽  
Vol 156 ◽  
pp. 107625
Author(s):  
Xiao-Feng Geng ◽  
Hu Ding ◽  
Xiao-Ye Mao ◽  
Li-Qun Chen

2021 ◽  
pp. 107754632199358
Author(s):  
Ali Fasihi ◽  
Majid Shahgholi ◽  
Saeed Ghahremani

The potential of absorbing and harvesting energy from a two-degree-of-freedom airfoil using an attachment of a nonlinear energy sink and a piezoelectric energy harvester is investigated. The equations of motion of the airfoil coupled with the attachment are solved using the harmonic balance method. Solutions obtained by this method are compared to the numerical ones of the pseudo-arclength continuation method. The effects of parameters of the integrated nonlinear energy sink-piezoelectric attachment, namely, the attachment location, nonlinear energy sink mass, nonlinear energy sink damping, and nonlinear energy sink stiffness on the dynamical behavior of the airfoil system are studied for both subcritical and supercritical Hopf bifurcation cases. Analyses demonstrate that absorbing vibration and harvesting energy are profoundly affected by the nonlinear energy sink parameters and the location of the attachment.


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