Simulation and Testing of a 6-Story Structure Incorporating a Coupled Two Mass Nonlinear Energy Sink

2012 ◽  
Author(s):  
Nicholas E. Wierschem ◽  
Jie Luo ◽  
Mohammad AL-Shudeifat ◽  
Sean Hubbard ◽  
Richard Ott ◽  
...  
Keyword(s):  
Linear Structure ◽  
Experimental Tests ◽  
Nonlinear Energy Sink ◽  
Degree Of Freedom ◽  
Nonlinear Element ◽  
Numerical Predictions ◽  
Wide Range ◽  
Modes Of Vibration ◽  
Energy Sink ◽  
Nonlinear Energy

The nonlinear energy sink (NES) is a passive device used to rapidly direct energy into higher modes of vibration and locally dissipate a significant portion of the impulsive shock energy induced in the primary, linear structure to which it is attached. The Type III NES is a two degree-of-freedom device comprised of two lightweight masses coupled together through an essentially nonlinear element. The lower mass in this two-mass arrangement is coupled to the linear structure through another essentially nonlinear element. This modification has been found to dramatically improve the performance of the NES to mitigate the shock when compared to a one degree-of-freedom NES device. The measure of effective damping of the linear structure indicates the ability of the NES to dissipate energy and reduce the response of the structure across a wide range of energies. Experimental tests have been performed to verify the numerical findings. Good agreement between numerical predictions and experimental observations validates the identified model of the NES.

Numerical and Experimental Investigation of a New Nonlinear Energy Sink for Passive Shock Mitigation

2012 ◽  
Author(s):  
Mohammad A. AL-Shudeifat ◽  
Nicholas Wierschem ◽  
Alexander F. Vakakis ◽  
Lawrence A. Bergman ◽  
Billie F. Spencer
Keyword(s):  
Linear Structure ◽  
Nonlinear Energy Sink ◽  
Initial Energy ◽  
Numerical Results ◽  
New Device ◽  
Numerical Predictions ◽  
Energy Sink ◽  
Experimental Findings ◽  
High Level ◽  
Nonlinear Energy

A new device functioning as an efficient nonlinear energy sink (NES) is explored here. The device consists of a mass coupled to a two-story linear test structure through a single-sided vibro-impact (VI) nonlinearity in one direction and a weak linear spring in both directions. This design is found to be more efficient for passive targeted energy transfer (TET) than existing NESs. It absorbs and rapidly dissipates a significant amount of the impulsive energy induced in the linear structure. In addition, some of this initial energy is pumped to higher modes of the structure and efficiently dissipated there. The numerical results have verified that the proposed single-sided VI NES maintains high level of performance over a broad range of high input energies. It performs near to its optimum even for severe induced shocks. Moreover, the numerical results have been experimentally verified; good agreement between numerical predictions and experimental findings was observed.

Enhanced Rotating Nonlinear Energy Sink

2016 ◽  
Author(s):  
Mohammad A. Al-Shudeifat ◽  
Adnan S. Saeed
Keyword(s):  
Radial Direction ◽  
Linear Structure ◽  
Nonlinear Energy Sink ◽  
Vertical Axis ◽  
Viscous Damping ◽  
Linear Coupling ◽  
Damping Coefficients ◽  
Wide Range ◽  
Energy Sink ◽  
Nonlinear Energy

An enhanced rotating nonlinear energy sink (NES) is numerically investigated in this study. The rotating NES in the literature is coupled with the associated linear structure by its nonlinear inertial coupling through a rigid arm that couples the rotating NES mass with the structure. Here, the coupling arm is assumed to be elastic. Consequently, the NES mass rotates about a fixed vertical axis and allowed to oscillate along the coupling arm in a radial direction. According to this modification, the rotating NES dissipates the transferred energy from the associated structure through its angular and radial viscous damping. Therefore, the modified rotating NES by elastic arm is found to absorb and dissipate more energy than the old one for a wide range of initial input energies induced into the associated linear structure. The arm length and the angular damping coefficient of the old rotating NES are optimized first by assuming a rigid coupling arm and later the stiffness and the damping coefficients in the radial direction are optimized accordingly. The obtained numerical results have shown a significant improvement in the rotating NES performance when the NES is allowed to oscillate through the coupling arm by a linear coupling restoring spring rather than locking the NES to a rigid arm.

Piecewise Nonlinear Energy Sink

2015 ◽  
Author(s):  
Mohammad A. Al-Shudeifat
Keyword(s):  
Dead Zone ◽  
Linear Structure ◽  
Nonlinear Energy Sink ◽  
Viscous Damping ◽  
Nonlinear Stiffness ◽  
Flexible Design ◽  
Energy Inputs ◽  
Energy Sink ◽  
The Dead ◽  
Nonlinear Energy

Symmetric piecewise nonlinearities are employed here to design highly efficient nonlinear energy sink (NES). These symmetric piecewise nonlinearities are usually called in the literature as dead-zone nonlinearities. The proposed dead-zone NES includes symmetric clearance about its equilibrium position in which zero stiffness and linear viscous damping are incorporated. At the boundaries of the symmetric clearance, the NES is coupled to the linear structure by either linear or nonlinear stiffness components in addition to similar viscous damping to that in the clearance zone. By this flexible design of the dead-zone NES, we obtain a considerable enhancement in the NES efficiency at moderate and severe energy inputs. Moreover, the dead-zone NES is also found here through numerical simulations to be more robust for damping and stiffness variations than the linear absorber and some other types of NESs.

A suspension system with quasi-zero stiffness characteristics and inerter nonlinear energy sink

2020 ◽  
pp. 107754632097290
Author(s):  
You-cheng Zeng ◽  
Hu Ding ◽  
Rong-Hua Du ◽  
Li-Qun Chen
Keyword(s):  
Integrated Control ◽  
Harmonic Approximation ◽  
Nonlinear Energy Sink ◽  
Suspension System ◽  
Degree Of Freedom ◽  
System Parameters ◽  
Suspension Systems ◽  
Control Scheme ◽  
Energy Sink ◽  
Nonlinear Energy

In this article, a novel vibration control scheme of suspension systems is proposed. It combines the advantages of quasi-zero stiffness isolator, nonlinear energy sink absorber, and inerter. This proposed scheme can achieve low transmissibility, low amplitude, and low additional weight and resolve the conflict between riding comfort and handling stability. Strong nonlinear vibration equations of a quarter-vehicle suspension system are established. It also presents the detailed process of high-order harmonic approximation to obtain steady-state responses. Moreover, approximate solutions are validated by a numerical method. Furthermore, based on riding comfort and handling stability, the following four suspension systems are evaluated and compared, namely, 2-degree-of-freedom quarter-vehicle model, 2-degree-of-freedom quarter-vehicle with quasi-zero stiffness isolator, 2-degree-of-freedom quarter-vehicle with inerter-nonlinear energy sink absorber, and 2-degree-of-freedom quarter-vehicle integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink. It is found that the integrated control scheme with quasi-zero stiffness and inerter-nonlinear energy sink can significantly improve the riding comfort and handling stability at the same time. In addition, the effects of system parameters are studied carefully. The results show that based on the reasonable design of the control system parameters, better riding comfort and handling stability can be obtained. In short, this article provides a theoretical basis for integrating quasi-zero stiffness isolators and inerter-nonlinear energy sink absorbers to improve the riding comfort and handling stability.

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

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.

Numerical Study of a Single-Sided Vibro-Impact Track Nonlinear Energy Sink Considering Horizontal and Vertical Dynamics

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Wenke Li ◽  
Nicholas E. Wierschem ◽  
Xinhui Li ◽  
Tiejun Yang ◽  
Michael J. Brennan
Keyword(s):  
Primary Structure ◽  
Numerical Study ◽  
Nonlinear Energy Sink ◽  
Horizontal Direction ◽  
Impact Surface ◽  
Wide Range ◽  
Quartic Polynomial ◽  
Energy Sink ◽  
The Impact ◽  
Nonlinear Energy

Abstract In this paper, the single-sided vibro-impact track nonlinear energy sink (SSVI track NES) is studied. The SSVI track NES, which is attached to a primary structure, has nonlinear behavior caused by the NES mass moving on a fixed track and impacting on the primary structure at an impact surface. Unlike previous studies of the SSVI track NES, both the horizontal and vertical dynamics of the primary structure are considered. A numerical study is carried out to investigate the way in which energy is dissipated in this system. Assuming a track shape with a quartic polynomial, an optimization procedure that considers the total energy dissipated during a time period is carried out, to determine the optimum NES mass and track parameter. It is found that there is dynamic coupling between the horizontal and vertical directions caused by the SSVI track NES motion. The vibrational energy, originally in the structure in the horizontal direction, is transferred to the vertical motion of the structure where it is dissipated. Considering that many civil and mechanical systems are particularly vulnerable to extreme loads in the horizontal direction, this energy transformation can be beneficial to prevent or limit damage to the structure. The effect on energy dissipation of the position of the impact surface in the SSVI track NES and the ratio of the vertical to horizontal stiffness in the primary structure are discussed. Numerical results demonstrate a robust and stable performance of the SSVI track NES over a wide range of stiffness ratios.

scholarly journals Parameter Variation on Nonlinear Energy Sink attached to Multiple Degree of Freedom System

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Martin Jahn ◽  
Lars Panning-von Scheidt ◽  
Jörg Wallaschek
Keyword(s):  
Nonlinear Energy Sink ◽  
Parameter Variation ◽  
Degree Of Freedom ◽  
Energy Sink ◽  
Nonlinear Energy

Numerical Investigation of Rotating Nonlinear Energy Sink for Shock Mitigation

2013 ◽  
Author(s):  
Mohammad A. Al-Shudeifat ◽  
Lawrence A. Bergman ◽  
Alexander F. Vakakis
Keyword(s):  
Energy Transfer ◽  
Linear Structure ◽  
Nonlinear Energy Sink ◽  
Initial Energy ◽  
Shock Mitigation ◽  
Nonlinear Targeted Energy Transfer ◽  
Primary Test ◽  
Energy Sink ◽  
Two Degree Of Freedom ◽  
Nonlinear Energy

Passive nonlinear targeted energy transfer (TET) is addressed here by investigating a lightweight rotating nonlinear energy sink (NES). The rotating sink mass has an essentially nonlinear inertial coupling with the two degree-of-freedom linear system (the primary test structure). The proposed rotating NES is numerically investigated where it is found to passively absorb and rapidly dissipate a considerable portion of the initial energy induced by impulse to the linear structure. The parameters of the rotating NES are optimized for the best performance in the vicinity of intermediate and high loads. The fundamental mechanism for significant energy transfer to the NES is its rotational mode; the oscillatory mode of the NES dissipates far less energy. The frequency-energy dependences are investigated through the frequency-energy plot (FEP). Early and strong resonance capture at the lowest modal frequency is observed between the rotator and the structure, at which a significant portion of the induced energy is transferred and dissipated by the rotator. The performance of this device is found to be comparable to existing, stiffness-based NES designs. However, this device is less complicated and more compact.

scholarly journals On the Effect of Nonlinear Energy Sink Damping in Seismic Vibration Attenuation

2021 ◽  
Author(s):  
Eliot Motato ◽  
Fabio G. Guerrero
Keyword(s):  
Nonlinear Energy Sink ◽  
Tuned Mass Dampers ◽  
Building Model ◽  
Wide Range ◽  
Vibration Attenuation ◽  
Different Types ◽  
Energy Sink ◽  
Shear Building ◽  
Model Subject ◽  
Nonlinear Energy

Abstract Nonlinear Energy Sinks (NESs) have been proposed for passively reducing the amplitude of vibrations in different types of structures. The main advantage of NES over traditional Tuned Mass Dampers (TMDs) lies in its capability to redistribute the vibrating energy inside a primary structure, what effectively reduces the amplitude of the structure oscillations over a wide range of frequencies. However, the performance of an NES can be substantially affected even by small variations on input energy as in the case of buildings under seismic ground excitation. In this work it is shown that the NES energy sensibility can be significantly reduced by properly selecting the NES damping coefficient. A three stories shear building model subject to seismic ground excitation is used to numerically study the effect that NES damping has on its vibration reduction performance.

scholarly journals Frequency Energy Plots of Dynamical Systems Attached to Piecewise Nonlinear Energy Sink

2021 ◽  
Author(s):  
Mohammed Ameen Ameen Al Shudeifat ◽  
Adnan Salem Saeed
Keyword(s):  
Normal Modes ◽  
Linear Structure ◽  
Nonlinear Energy Sink ◽  
Nonlinear Normal Modes ◽  
Dynamical Behaviour ◽  
Subharmonic Resonance ◽  
Numerical Continuation ◽  
Continuation Methods ◽  
Energy Sink ◽  
Nonlinear Energy

Abstract The frequency-energy plots (FEPs) of two-degree-of-freedom linear structures attached to piecewise nonlinear energy sink (PNES) are generated here and thoroughly investigated. This study provides the FEP analysis of such systems for further understanding of nonlinear targeted energy transfer (TET) by the PNES. The attached PNES incorporates a symmetrical clearance zone of zero stiffness content about its equilibrium position where the boundaries of the zone are coupled with linear structure by linear stiffness elements. In addition, linear viscous damping is selected to be continuous during PNES mass oscillation. The underlying nonlinear dynamical behaviour of the considered structure-PNES systems is investigated by generating the fundamental backbone curves of the FEP and the bifurcated subharmonic resonance branches using numerical continuation methods. Accordingly, interesting dynamical behaviour of the nonlinear normal modes (NNMs) of the structure-PNES system on different backbones and subharmonic resonance branches has been observed. In addition, the imposed wavelet transform frequency spectrums on the FEPs have revealed that the TET takes place where it is dominated by the nonlinear action of the PNES.

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