scholarly journals Bistable Nonlinear Energy Sink Using Magnets and Linear Springs: Application to Structural Seismic Control

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Y. Y. Chen ◽  
W. Zhao ◽  
C. Y. Shen ◽  
Z. C. Qian
Keyword(s):  
Permanent Magnets ◽  
Nonlinear Energy Sink ◽  
Vibration Absorber ◽  
Control Performance ◽  
Frame Model ◽  
Seismic Control ◽  
Mass Damper ◽  
Energy Sink ◽  
Shear Frame ◽  
Nonlinear Energy

Nonlinear energy sink (NES) has proven to be very effective in reducing the vibration response of structures. In this paper, a magnetic bistable nonlinear energy sink (BNES) that composed of a guided moving mass attached with linear springs and permanent magnets is proposed. To assess the seismic control performance of the proposed BNES, a shear frame model equipped with the proposed BNES is compared with the same shear frame model equipped with an optimized cubic NES and with a linear tuned mass damper (TMD) system. The results show that, in the idealized situation, where the mass and stiffness is clearly defined (no uncertainty), the BNES can achieve similar performance as a thoroughly in-tuned TMD system. Moreover, in the detuned condition, due to broadband high internal resonance capability, the proposed BNES can outperform the linear TMD and the cubic NES. The study demonstrates that the proposed BNES can be used as an efficient passive vibration absorber for structural seismic control.

An energy-robust nonlinear energy sink with inerter

2021 ◽  
Author(s):  
Jingjing Wang ◽  
Bin Wang ◽  
Yuqiang Zheng
Keyword(s):  
Nonlinear Energy Sink ◽  
Frame Structure ◽  
Seismic Excitation ◽  
Inertial Effect ◽  
Building Structures ◽  
Control Performance ◽  
Mass Damper ◽  
Physical Mass ◽  
Energy Sink ◽  
Nonlinear Energy

<p>This paper presents an inerter-enhanced nonlinear mass damper developed from an asymmetric nonlinear energy sink (Asym NES), which adds an inerter between the auxiliary mass of the Asym NES and a fixed point. The size of the Asym NES-inerter (Asym NESI) can be significantly reduced due to the inerter providing a large inertial effect with limited physical mass involved. The design concept of the Asym NESI will be described first. Subsequently, the performance of the Asym NESI will be evaluated on a three-story frame structure through computational investigations. Results show that the Asym NESI exhibites strong robustness against changes in both energy level and structural frequency. Driven by the inertial effect, the Asym NESI is excellent in control performance and installation flexibility under the seismic excitation considered, demonstrating great potential as a superior control strategy for response mitigation of building structures.</p><p><br clear="none"/></p>

Nonlinear Torsional Vibration Absorber for Flexible Structures

2018 ◽  
Vol 86 (2) ◽  
Author(s):  
Xiao-Ye Mao ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
High Efficiency ◽  
Rotation Angle ◽  
Flexible Structures ◽  
Nonlinear Energy Sink ◽  
Flexible Structure ◽  
Vibration Absorber ◽  
Special Perturbation ◽  
Energy Sink ◽  
Simulation Parameters ◽  
Nonlinear Energy

A new kind of nonlinear energy sink (NES) is proposed to control the vibration of a flexible structure with simply supported boundaries in the present work. The new kind of absorber is assembled at the end of structures and absorbs energy through the rotation angle at the end of the structure. It is easy to design and attached to the support of flexible structures. The structure and the absorber are coupled just with a nonlinear restoring moment and the damper in the absorber acts on the structure indirectly. In this way, all the linear characters of the flexible structure will not be changed. The system is investigated by a special perturbation method and verified by simulation. Parameters of the absorber are fully discussed to optimize the efficiency of it. For the resonance, the maximum motion is restrained up to 90% by the optimized absorber. For the impulse, the vibration of the structure could attenuate rapidly. In addition to the high efficiency, energy transmits to the absorber uniaxially. For the high efficiency, convenience of installation and the immutability of linear characters, the new kind of rotating absorber provides a very good strategy for the vibration control.

Sommerfeld Effect and Passive Energy Reallocation in a Self-Synchronizing System

2018 ◽  
Author(s):  
Anubhab Sinha ◽  
Saurabh Kumar Bharti ◽  
Arun Kumar Samantaray ◽  
Ranjan Bhattacharyya
Keyword(s):  
Nonlinear Energy Sink ◽  
Power Input ◽  
Vibration Absorber ◽  
Sommerfeld Effect ◽  
Structural Vibrations ◽  
Dynamic Vibration Absorber ◽  
Jump Phenomena ◽  
Energy Sink ◽  
Nonlinear Energy ◽  
Base Structure

Two eccentric rotors are mounted rigidly on a common vibrating base structure. Each of these rotors are separately driven by two motors, which are by nature non-ideal. Although power input for both rotors are different, the two rotors acquire the same speed via communication through the energized vibrating base. The phenomena is known as ‘self-synchronization’. Additionally, the presence of two non-ideal drives within the vibrating system also lead to the onset of the nonlinear jump phenomena (formally known as the Sommerfeld effect). Numerical simulations are carried out on a model developed on MSC Adams. From the generated responses, an overview of ‘self-synchronization’ as well as the various modes of synchronization are studied adjacent to the nature of Sommerfeld effect inherent within this system. The aim is to reduce the structural vibrations, mainly by virtue of self-synchronization. Henceforth, the behavior of the synchronized system is also examined in the presence of two secondary vibration reducing devices — a tuned Dynamic Vibration Absorber (DVA) and a Nonlinear Energy Sink (NES). Both are designed to passively absorb the excess vibrating energy from the synchronized system, at the onset of resonance.

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.

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

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.

A magnetic Bi-stable nonlinear energy sink for structural seismic control

2020 ◽  
Vol 473 ◽  
pp. 115233 ◽  
Author(s):  
Yang-Yang Chen ◽  
Zhi-Chao Qian ◽  
Wei Zhao ◽  
Chia-Ming Chang
Keyword(s):  
Nonlinear Energy Sink ◽  
Seismic Control ◽  
Energy Sink ◽  
Nonlinear Energy

Design Procedure of a Nonlinear Vibration Absorber Using Bifurcation Analysis: Application to the Drill-String System

2009 ◽  
Author(s):  
Re´gis Viguie´ ◽  
Gae¨tan Kerschen
Keyword(s):  
Design Procedure ◽  
Nonlinear Energy Sink ◽  
Drill String ◽  
Vibration Absorber ◽  
Nonlinear Structures ◽  
Targeted Energy Transfer ◽  
Vibration Level ◽  
Analysis Application ◽  
Energy Sink ◽  
Nonlinear Energy

A nonlinear energy sink (NES) is characterized by its ability to passively realize targeted energy transfer as well as multimodal damping. This latter feature seems to make this device very well suited for reducing the vibration level of MDOF linear and nonlinear structures. The perspective of dealing with such primary structures requires the development of an efficient NES design procedure. This paper poses the basis of such a procedure that is applied to the vibration mitigation of a drill-string system, using the software MatCont.

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