SHOCK ISOLATION THROUGH PASSIVE ENERGY PUMPING CAUSED BY NONSMOOTH NONLINEARITIES

2005 ◽  
Vol 15 (06) ◽  
pp. 1989-2001 ◽  
Author(s):  
F. GEORGIADIS ◽  
A. F. VAKAKIS ◽  
D. M. MCFARLAND ◽  
L. BERGMAN
Keyword(s):  
Vibration Absorber ◽  
Primary System ◽  
Linear Vibration ◽  
Practical Applications ◽  
Energy Pumping ◽  
Weakly Coupled ◽  
Nonlinear Energy Pumping ◽  
Shock Isolation ◽  
Isolation Performance ◽  
Nonlinear Energy

We investigate shock isolation designs based on nonlinear energy pumping caused by nonsmooth stiffness elements. In particular, we numerically study the shock isolation properties of a primary linear system of two coupled nonconservative oscillators with weakly coupled attachments possessing clearance nonlinearities. Under shock excitation the nonlinear attachments (termed nonlinear energy sinks — NESs) can be designed to absorb a significant portion of the input energy, thus enhancing the shock isolation performance of the primary system. In contrast to the classical linear vibration absorber whose operation is restricted to narrowband frequency ranges, the NESs are capable of efficiently absorbing energies caused by transient broadband disturbances, a feature that facilitates their implementation in practical applications. Moreover, the nonsmooth nonlinearities considered in this work are easily implementable since they are realized by means of linear stiffness elements.

Shock Isolation Through Passive Energy Pumping in a System With Piecewise Linear Stiffnesses

2003 ◽  
Author(s):  
Fotios Georgiadis ◽  
Alexander F. Vakakis ◽  
D. Michael McFarland ◽  
Lawrence Bergman
Keyword(s):  
Piecewise Linear ◽  
Primary System ◽  
Linear Vibration ◽  
Practical Applications ◽  
Energy Pumping ◽  
Weakly Coupled ◽  
Nonlinear Energy Pumping ◽  
Shock Isolation ◽  
Isolation Performance ◽  
Nonlinear Energy

We investigate shock isolation designs based on nonlinear energy pumping caused by piecewise stiffness elements. In particular, we numerically study the shock isolation properties of a primary linear system of two coupled non-conservative oscillators with weakly coupled attachments possessing clearance nonlinearities. Under shock excitation the nonlinear attachments (termed nonlinear energy sinks – NESs) can be designed to absorb a significant portion of the input energy, thus enhancing the shock isolation performance of the primary system. In contrast to the classical linear vibration absorber whose operation is restricted to narrowband frequency ranges, the NESs are capable of efficiently absorbing energies caused by transient broadband disturbances, a feature that facilitates their implementation in practical applications. Moreover, the non-smooth nonlinearities considered in this work are easily implementable since they are realized by means of linear stiffness elements.

Study on Dynamics of a Nonlinear Damping Absorber Coupled to the Linear System

2010 ◽  
Vol 143-144 ◽  
pp. 763-767
Author(s):  
Si Mi Tang ◽  
Shi Jian Zhu ◽  
Jing Jun Lou
Keyword(s):  
Linear System ◽  
Engineering Application ◽  
Nonlinear Energy Sink ◽  
Nonlinear Damping ◽  
Vibration Absorber ◽  
Energy Pumping ◽  
Nonlinear Energy Pumping ◽  
And Performance ◽  
Quadratic Damping ◽  
Nonlinear Energy

The dynamics of a two degree-of-freedom (DOF) system consisting of a linear system coupled with a quadratic damping vibration absorber is studied. The nonlinear energy pumping phenomenon is verified by simulation and analyzed by Hilbert Transform. Performance of the quadratic damping absorber that is able to absorb vibration over a broad range of frequency (nonlinear energy sink, NES) is studied, and the results are compared with that of the classical linear vibration absorber. The relationship between parameters and performance of the absorber is analyzed, that is significant for engineering application.

Shock Isolation Through the Use of Nonlinear Energy Sinks

2003 ◽  
Vol 9 (1-2) ◽  
pp. 79-93 ◽  
Author(s):  
Alexander F. Vakakis
Keyword(s):  
Early Stage ◽  
A Priori ◽  
Primary System ◽  
Global Dynamics ◽  
Nonlinear Stiffness ◽  
Dynamic Phenomenon ◽  
Dual Mode ◽  
Energy Pumping ◽  
Shock Isolation ◽  
Nonlinear Energy

We consider shock isolation designs based on the use of nonlinear energy sinks (NESs). These are a priori determined points of a system where unwanted disturbances are transmitted (“pumped”) and then eliminated by passive or active means. The underlying dynamic phenomenon that causes nonlinear energy to pump into a sink is resonance capture on a 1:1 resonance manifold of the dynamics. In this work, essentially nonlinear stiffness elements are used to couple the NES with the primary system in order to achieve robust energy pumping, in a sufficiently fast timescale. “Fast” energy pumping at the early stage of the motion is important in order to achieve the shock isolation objectives. The proposed shock isolation design is practical and realizable. Its modular form enables the alteration of the global dynamics of a system by attaching a number of local NESs. The proposed design has the additional interesting feature of dual mode shock isolation, e.g., the capacity to significantly reduce the level of unwanted disturbances initiated at different points of the system.

Study on Nonlinear Energy Pumping of the Vibration System with Cubic Damping Absorber

2010 ◽  
Vol 34-35 ◽  
pp. 1243-1247 ◽  
Author(s):  
Si Mi Tang ◽  
Shi Jian Zhu ◽  
Jing Jun Lou
Keyword(s):  
Vibration System ◽  
Optimal Parameters ◽  
Time Frequency ◽  
Energy Pumping ◽  
Pumping Efficiency ◽  
Nonlinear Energy Pumping ◽  
Two Degree Of Freedom ◽  
Nonlinear Energy ◽  
Cubic Stiffness ◽  
Main Oscillator

The nonlinear energy pumping in a two-degree-of-freedom system comprising a damped linear oscillator coupled to cubic damping absorber is studied. It is verified that the nonlinear pumping energy can be performed by cubic damping absorber besides cubic stiffness absorber. The resonance capture is verified by time-frequency analysis (Hilbert Transform). The energy pumping efficiency is put forward for quantitative analysis, and the optimal parameters of system are obtained. The amplitude of main oscillator can be attenuated in a very short duration. The result may be significative for engineering implementation.

Optimal Vibration Control and Energy Scavenging Using Collocated Nonlinear Energy Sinks and Piezoelectric Elements

2018 ◽  
Author(s):  
Zahra Nili Ahmadabadi ◽  
Siamak Esmaeilzadeh Khadem
Keyword(s):  
Piezoelectric Element ◽  
Dissipated Energy ◽  
Vibration Energy ◽  
Energy Scavenging ◽  
Optimization Approach ◽  
Energy Harvesters ◽  
Energy Pumping ◽  
Nonlinear Energy Pumping ◽  
Energy Dissipated ◽  
Nonlinear Energy

This paper presents an optimal design for a system comprising multiple nonlinear energy sinks (NESs) and piezoelectric-based vibration energy harvesters attached to a free–free beam under shock excitation. The energy harvesters are used for scavenging vibration energy dissipated by the NESs. Grounded and ungrounded configurations are examined, and the systems parameters are optimized globally to maximize the dissipated energy by the NESs. The performance of the system was optimized using a dynamic optimization approach. Compared to the system with only one NES, using multiple NESs resulted in a more effective realization of nonlinear energy pumping particularly in the ungrounded configuration. Having multiple piezoelectic elements also increased the harvested energy in the grounded configuration relative to the system with only one piezoelectric element.

Steady-State Dynamics of Smooth and Non-Smooth Systems With Strong Nonlinearities

2003 ◽  
Author(s):  
Xiaoai Jiang ◽  
Alexander F. Vakakis
Keyword(s):  
Steady State ◽  
Vibration Isolation ◽  
High Order ◽  
State Behavior ◽  
Energy Pumping ◽  
Nonlinear Energy Pumping ◽  
Clearance Nonlinearity ◽  
High Order Nonlinearity ◽  
Odd Nonlinearity ◽  
Nonlinear Energy

The nonlinear energy sinks (NESs) with strong essential stiffness nonlinearities have been shown to result in vibration isolation in the studied system. In comparison, we also studied the steady-state dynamic response of a system with its smooth high-order odd nonlinearity replaced with the best fitted nonsmooth “clearance nonlinearity”. The analysis was based on the complexification technique and the separation of the dynamic terms into the “slow-varying” and the “fast-varying” components. We found that the steady-state behavior of a system with the non-smooth NES resembles that of the system with the smooth high-order nonlinearity, preserving the nonlinear energy-pumping feature. This finding paves the way for constructing practical NESs and applying them to practical vibration-isolation problems.

Passive Vibration Control Through Nonlinear Energy Pumping

2003 ◽  
Author(s):  
Alexander F. Vakakis ◽  
D. Michael McFarland ◽  
Lawrence Bergman ◽  
Leonid Manevitch ◽  
Oleg Gendelman
Keyword(s):  
Vibration Control ◽  
Nonlinear Energy Sink ◽  
New Paradigm ◽  
Energy Pumping ◽  
Nonlinear Energy Pumping ◽  
Mechanical Oscillators ◽  
Damped Systems ◽  
Mode Energy ◽  
Multi Mode ◽  
Nonlinear Energy

We examine vibration control through passive energy pumping in a system of damped coupled oscillators. This is a one-way, passive and irreversible energy flow from a linear main system to a nonlinear attachment that acts, in essence, as a nonlinear energy sink (NES). Energy pumping is caused by 1:1 resonance captures on resonant manifolds of the damped systems. We show that the NES is capable of absorbing significant portions of the energies generated by transient, broadband external excitations. We present numerical simulations of single- and multi-mode energy pumping, that involve isolated resonance captures or resonance capture cascades, respectively. In addition, we discuss methodologies for enhancing the nonlinear energy pumping phenomenon by properly selecting the system parameters. The described technique of passively localizing and locally eliminating externally induced energy provides a new paradigm for vibration and shock isolation of mechanical oscillators.

On an Active Control for a Structurally Nonlinear Mechanical System, Taking Into Account an Energy Pumping

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
S. N. J. Costa ◽  
J. M. Balthazar
Keyword(s):  
Active Control ◽  
Impact Load ◽  
Nonlinear Energy Sink ◽  
Energy Pumping ◽  
Nonlinear Mechanical ◽  
Nonlinear Energy Pumping ◽  
Nonlinear Mechanical System ◽  
Optimal Linear ◽  
Energy Sink ◽  
Nonlinear Energy

The purpose of this work is to investigate the control of the oscillations and the suppression of vibrations in damped and coupled oscillators. In this sense, we look into the potential of using a nonlinear energy sink in combination with an optimal linear control for nonlinear system to suppress structure vibrations under an impact load. As a result, we obtain that the nonlinear energy pumping (a one-way passive and almost irreversible energy flow from a linear main system to a nonlinear attachment that acts as a nonlinear energy sink) can be enhanced with the help of appropriate active control. The numerical results show the effectiveness of the approach presented here.

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