Targeted Energy Transfer With Several NES in Parallel: Theory and Experiments

2009 ◽  
Author(s):  
Alireza Ture Savadkoohi ◽  
Stephane Pernot ◽  
Claude Henri Lamarque
Keyword(s):  
Nonlinear Energy Sink ◽  
Single Degree Of Freedom ◽  
Strongly Nonlinear ◽  
Seismic Engineering ◽  
Energy Pumping ◽  
In Series ◽  
Energy Sink ◽  
Energy Activation ◽  
Nonlinear Energy ◽  
Theory And Experiments

The crucial point in the field of seismic engineering is to diminish the induced vibration energy as much as possible in a fast and almost irreversible manner. Recently the concept of Nonlinear Energy Sink (NES) has been developed such that the imposed energy to a linear single Degree of Freedom (DoF) substructure is transferred to one or series of strongly nonlinear light attachments; the mechanism is based on a 1:1 resonance capture. Nonlinear attachments can be designed to passively vibrate with any frequency; hence the system is efficient for both of transient and periodic excitations. Some drawbacks of these systems are as follows: they cannot kill the first peak of oscillation in the free time response that is linked to the energy activation of NES; moreover, the transformation of energy vanishes in time due to decrease of the strength of energy pumping. Using NES in series even cannot accelerate the phenomenon of energy pumping and some strange behavior due to the delay in the cooperation of NES in series is noticed. In this study, the transient dynamic behavior of multiple DoF systems with trees of parallel NES at each DoF is investigated, then experimental and numerical results of a four DoF structure with two parallel NES at the top floor are demonstrated and commented upon.

Nonlinear Energy Sink With Uncertain Parameters

2006 ◽  
Vol 1 (3) ◽  
pp. 187-195 ◽  
Author(s):  
E. Gourdon ◽  
C. H. Lamarque
Keyword(s):  
Normal Modes ◽  
Nonlinear Energy Sink ◽  
Nonlinear Normal Modes ◽  
Supplementary Information ◽  
Uncertain Parameters ◽  
Energy Pumping ◽  
Energy Sink ◽  
Nonlinear Normal ◽  
Polynomial Chaos Expansions ◽  
Nonlinear Energy

The effects of a nonlinear energy sink during the instationary regime are analyzed by introducing uncertain parameters to verify the robustness of the transient spatial energy transfer when parameters are not well known. It was shown that it is possible to passively absorb energy from a linear nonconservative system (damped) structure to a nonlinear attachment weakly coupled to the linear one. This rapid and irreversible transfer of energy, named energy pumping, is studied by taking into account uncertainties on parameters, especially damping (since damping plays a great role and there is a lack of knowledge about it). In essence, the nonlinear subsystem acts as a passive nonlinear energy sink for impulsively applied external vibrational disturbances. The aim is to be able to apply energy pumping in practice where the nonlinear attachment realization will never perfectly reflect the design. Since strong nonlinearities are involved, polynomial chaos expansions are used to obtain information about random displacements. Not only are numerical investigations done, but nonlinear normal modes and the role of damping are also analytically studied, which confirms the numerical studies and shows the supplementary information obtained compared to a parametrical study.

Asymmetric Magnet-Based Nonlinear Energy Sink

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad A. AL-Shudeifat
Keyword(s):  
Permanent Magnets ◽  
Nonlinear Energy Sink ◽  
Weakly Nonlinear ◽  
Strongly Nonlinear ◽  
Shock Mitigation ◽  
Energy Inputs ◽  
Energy Sink ◽  
Dynamic Structures ◽  
Nonlinear Energy ◽  
Weakly Linear

The nonlinear energy sink (NES) is a light-weighted device used for shock mitigation in dynamic structures through its passive targeted energy transfer (TET) mechanism. Here, a new design for the NES is introduced based on using an asymmetric NES force. This force is strongly nonlinear in one side of the NES equilibrium position, whereas it is either weakly nonlinear or weakly linear in the other side. This is achieved by introducing the asymmetric magnet-based NES in which the asymmetric nonlinear magnetic repulsive force is generated by two pairs of aligned permanent magnets. Consequently, this proposed design is found to provide a considerable enhancement in the shock mitigation performance compared with the symmetric stiffness-based NESs for broadband energy inputs.

Effects of bi-stable grounded nonlinear energy sink on energy dissipation of the system

2021 ◽  
pp. 146441932110460
Author(s):  
Arash Khalatbari ◽  
Amir Jalali ◽  
Habib Ahmadi ◽  
Kamran Foroutan
Keyword(s):  
Energy Dissipation ◽  
Total Energy ◽  
Invariant Manifolds ◽  
Equations Of Motion ◽  
Nonlinear Energy Sink ◽  
Multiple Scale ◽  
Excitation Amplitude ◽  
Energy Pumping ◽  
Energy Sink ◽  
Nonlinear Energy

In this paper, one of the most efficient passive absorbers, called nonlinear energy sink (NES), is analytically studied. A two-degree-of-freedom system is considered which consists of a linear oscillator (LO) with a base excitation and an NES, called grounded NES (GNES), which is connected to the ground with a nonlinear spring. In this study, we proposed a new arrangement of potential elements in GNES and studied invariant manifolds of the system, as well as the energy absorption performance of the NES. The system is considered in the vicinity of 1:1 resonance to investigate the strongly modulated response (SMR). To this end, after obtaining the equations of motion, the Manevitch complex variable and multiple scale method are applied to solve the equations, analytically. Then, the slow invariant manifold (SIM) is obtained. Also, the energy dissipation ratio of the NES and the percentage of the instantaneous total energy stored in the NES are calculated via the time-amplitude diagram. The results show that when the nonlinear effect decreases, the occurrence of energy pumping is less probable. Also, when the excitation amplitude decreases, the percentage of the instantaneous total energy stored in the NES increases as well as the amount of energy dissipation.

Piezoelectric Actuated Nonlinear Energy Sink With Tunable Attenuation Efficiency

2019 ◽  
Vol 87 (2) ◽  
Author(s):  
Jian Zhao ◽  
Ming Lyu ◽  
Hongxi Wang ◽  
Najib Kacem ◽  
Yu Huang ◽  
...  
Keyword(s):  
Nonlinear Energy Sink ◽  
Mathematic Model ◽  
Threshold Value ◽  
Excitation Amplitude ◽  
Wide Frequency Range ◽  
Application Range ◽  
High Attenuation ◽  
Energy Pumping ◽  
Energy Sink ◽  
Nonlinear Energy

Abstract Comparing to linear vibration absorbers, nonlinear energy sinks (NESs) have attracted worldwide attention for their intrinsic characteristics of targeted energy transfer or energy pumping in a relatively wide frequency range. Unfortunately, they are highly dependent on the vibration amplitude to be attenuated and will play its role only if the external load exceeds a specific threshold value. Different from the passive bistable NES, a novel piezoelectric nonlinear energy sink (PNES) is designed by introducing in-phase actuation to compensate or enhance the external vibration loads, thus triggering the NES operating in high attenuation efficiency. The nonlinear mathematic model of the PNES is established for investigating the dynamic response and determining the threshold compensation strategy. And the results show that the maximum attenuation efficiency can be improved by 58.16% compared to the traditional passive NES. Also, the amplitude-dependent coefficient (ADC) can be significantly reduced to 0.33 from 1.0, which means that the PNES can effectively mitigate vibrations even when the excitation amplitude is 67% smaller than the original threshold value. Finally, the feasibility of the in-phase compensation method is experimentally validated, which can further expand the application range of NES.

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.

Efficient Targeted Energy Transfer With Parallel Nonlinear Energy Sinks: Theory and Experiments

2011 ◽  
Vol 6 (4) ◽  
Author(s):  
Bastien Vaurigaud ◽  
Alireza Ture Savadkoohi ◽  
Claude-Henri Lamarque
Keyword(s):  
Energy Transfer ◽  
Analytical Method ◽  
Nonlinear Energy Sink ◽  
Prototype System ◽  
Targeted Energy Transfer ◽  
Resonance Capture ◽  
Prototype Structure ◽  
Energy Sink ◽  
Nonlinear Energy ◽  
Theory And Experiments

In this paper the targeted energy transfer (TET) phenomenon between a linear multi-DOF master structure and several slave parallel nonlinear energy sink (NES) devices during a 1:1 resonance capture is investigated. An analytical method is proposed for tuning optimal NES parameters, which leads to efficient TETs. Then, the procedure is intentionally narrowed for a 4DOF master structure with two parallel NESs at the last DOF in order to grasp optimum NES parameters of a prototype structure that is built and tested at the Civil Engineering and Building Department Laboratory of the ENTPE. The aim is to control the first mode of the compound nonlinear prototype system by demonstrating the efficiency of designed parallel NESs by the suggested method.

Enhanced Targeted Energy Transfer by Vibro Impact Cubic Nonlinear Energy Sink

2018 ◽  
Vol 10 (06) ◽  
pp. 1850061 ◽  
Author(s):  
Y. M. Wei ◽  
X. J. Dong ◽  
P. F. Guo ◽  
Z. K. Peng ◽  
W. M. Zhang
Keyword(s):  
Energy Transfer ◽  
Energy Absorption ◽  
Nonlinear Energy Sink ◽  
Targeted Energy Transfer ◽  
Analytical Treatment ◽  
Efficient Manner ◽  
Energy Pumping ◽  
Energy Sink ◽  
Two Degree Of Freedom ◽  
Nonlinear Energy

Passive targeted energy transfer (TET) that describes a highly efficient manner of energy absorption is considerably enhanced by a new form of absorber proposed in this paper. The absorber is attached to the primary linear oscillator (LO) through cubic stiffness and bilateral barriers that set to induce vibro-impact (VI). Both essential nonlinearity and non-smooth nonlinearity are considered. Energy pumping phenomenon is found, and complexification averaging method is used to give an analytical treatment for the essential stiffness nonlinearity. At a low level of impulse excitation where energy pumping of nonlinear energy sink (NES) does not occur, by introducing VI energy pumping is brought up. At the optimal TET state, the vibro-impact cubic (VIC) absorber improves the efficiency of cubic NES on energy reduction to a certain degree. For a two-degree-of-freedom LO, the new absorber can absorb most energy of the broadband excitation which is a novel improvement compared with normal NES. Broadband excitations like input with sufficient bandwidth and random signals are found to be absorbed extensively by the VIC NES, meaning that the VIC NES as a nonlinear passive vibration absorber can be very efficient on broadband vibration energy absorption.

Experimental Investigation of Low Frequency Noise Reduction Using a Nonlinear Vibroacoustic Absorber

2011 ◽  
Author(s):  
Sergio Bellizzi ◽  
Bruno Cochelin ◽  
Philippe Herzog ◽  
Pierre-Olivier Matte´i ◽  
Ce´dric Pinhe`de
Keyword(s):  
Vibrational Energy ◽  
Low Frequency ◽  
Nonlinear Energy Sink ◽  
Acoustic Medium ◽  
Frequency Noise ◽  
Primary System ◽  
Strongly Nonlinear ◽  
Energy Pumping ◽  
Energy Sink ◽  
Damped Oscillator

This work deals with the energy pumping phenomenon for acoustical applications. The concept of energy pumping is to passively reduce the vibrations of a primary system by attaching to it an essentially nonlinear damped oscillator also named Nonlinear Energy Sink (NES) creating a strongly nonlinear coupling which localizes and dissipates the vibrational energy. In the context of acoustics, a vibroacoustic coupling is used. In an earlier work, we showed experimentally that a loudspeaker used as a Suspended Piston (SP) working outside its range of linearity can be used as a NES. In this work, the performance and efficiency of a SP NES is studied numerically and experimentally. The considered acoustic medium is a resonant pipe. The coupling between the pipe and the NES is ensured acoustically by a small acoustic compliance (the air in a coupling box). Various observed aspects of energy pumping are presented: behavior under sinusoidal forcing, pumping threshold, resonance capture and transient response. As a SP NES technology permits an easy control of the moving mass of the NES, the effect of this parameter is also studied.

Sign in / Sign up

Export Citation Format

Share Document