scholarly journals Design, Experiment, and Improvement of a Quasi-Zero-Stiffness Vibration Isolation System

2020 ◽  
Vol 10 (7) ◽  
pp. 2273 ◽  
Author(s):  
Shuai Wang ◽  
Wenpen Xin ◽  
Yinghao Ning ◽  
Bing Li ◽  
Ying Hu
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Linear Spring ◽  
Isolation Effects ◽  
Magnetic Rings ◽  
The Relationship ◽  
Force Displacement

This paper proposes a new kind of quasi-zero-stiffness (QZS) isolation system that has the property of low-dynamic but high-static stiffness. The negative stiffness was produced using two magnetic rings, the magnetization of which is axial. First, the force–displacement characteristic of the two coupled magnetic rings was developed and the relationship between the parameters of the magnetic rings and the stiffness of the system was investigated. Then, the dynamic response of the QZS was analyzed. The force transmissibility of the system was calculated and the effects of the damping ratio and excitation amplitude on the isolation performance were investigated. The prototype of the QZS system was developed to verify the isolation effects of the system based on a comparison with a linear vibration isolation platform. Lastly, the improvement of the QZS system was conducted based on changing the heights of the ring magnets and designing a proper non-linear spring. The analysis shows the QZS system after improvement shows better isolation effects than that of the non-improved system.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

Development of Vibration Isolator With Controllable Stiffness Using Permanent Magnets and Coils

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Kai Meng ◽  
Yi Sun ◽  
Huayan Pu ◽  
Jun Luo ◽  
Shujin Yuan ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Permanent Magnets ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stealth Technology ◽  
Active Vibration ◽  
Magnetic Rings

In this study, a novel vibration isolator is presented. The presented isolator possesses the controllable stiffness and can be employed in vibration isolation at a low-resonance frequency. The controllable stiffness of the isolator is obtained by manipulating the negative stiffness-based current in a system with a positive and a negative stiffness in parallel. By using an electromagnetic device consisting of permanent magnetic rings and coils, the designed isolator shows that the stiffness can be manipulated as needed and the operational stiffness range is large in vibration isolation. We experimentally demonstrate that the modeling of controllable stiffness and the approximation of the negative stiffness expressions are effective for controlling the resonance frequency and the transmissibility of the vibration isolation system, enhancing applications such as warship stealth technology, vehicles suspension system, and active vibration isolator.

Numerical Study on the Application of Chaos in Line Spectrum Reduction

2009 ◽  
Author(s):  
Jingjun Lou ◽  
Shijian Zhu
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Numerical Study ◽  
Excitation Amplitude ◽  
Point Of View ◽  
Line Spectrum ◽  
Chaotic State ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Two Degree Of Freedom

The application of chaos method in line spectrum reduction is numerically studied. The nonlinear dynamics and the power flow transmissibility of a two-degree-of-freedom vibration isolation system with nonlinear spring are analyzed. The dynamic behavior distribution chart of the system is obtained. Cascades of bifurcation of the system with different excitation amplitude are also gained. The isolation effectiveness is analyzed from the point of view of energy. The numerical results show that the reduction of the line spectrum in chaotic state is much greater than that in non-chaotic state.

An efficient method for estimating the damping ratio of a vibration isolation system

2020 ◽  
Vol 21 (1) ◽  
pp. 103 ◽  
Author(s):  
Qiang Yu ◽  
Dengfeng Xu ◽  
Yu Zhu ◽  
Gaofeng Guan
Keyword(s):  
Efficient Method ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Resonance Peak ◽  
Estimation Methods ◽  
Mathematical Relationship ◽  
Isolation System ◽  
Vibration Isolation System ◽  
At Resonance ◽  
Practical Engineering

As the damping ratio determines the response of a vibration isolation system at resonance, it is very necessary to estimate the damping ratio quickly and economically for an evaluation of the effectiveness to adjust the damping in practical engineering applications. An efficient method named the “ζ-Tr” method with the characteristics of simple operation and a high accuracy is introduced to estimate the damping ratio in this paper. According to the transmissibility curve, the specific mathematical relationship in which the value of the resonance peak corresponds to the value of the damping ratio is analysed theoretically. In this case, the recognition of the resonance peak can be used to directly estimate the damping ratio without an approximation or simplification. The “ζ-Tr” method is faster, more accurate and less costly than other estimation methods. Finally, the correctness of the “ζ-Tr” method is verified by a simulation and an experiment.

scholarly journals The transmissibility of a vibration isolation system with ball-screw inerter based on complex mass

2018 ◽  
Vol 37 (4) ◽  
pp. 1097-1108 ◽  
Author(s):  
Huabing Wen ◽  
Junhua Guo ◽  
Yang Li ◽  
Yue Liu ◽  
Kun Zhang
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Experimental Tests ◽  
Experimental Results ◽  
Ball Screw ◽  
Type Ii ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Complex Mass ◽  
Isolation Systems

The wide application of the ball-screw inerter for vibration isolation has made it increasingly important to precisely determine the vibration transmissibility of the isolation system. In this reported work, the transmissibility of a vibration isolation system containing an inerter was predicted by using a complex mass M* in the calculations. The reported theoretical analysis showed that in the design of the type II inerter-spring-damper and inerter-rubber vibration isolation systems, the inertance-mass ratio must be less than twice the damping ratio to achieve improved vibration isolation performance when designing the system. To validate the findings, experimental tests were conducted on the type II inerter-spring-damper and inerter-rubber vibration isolation systems with ball-screw inerter. The experimental results showed that, based on M*, the transmissibility of these two systems was close to the experimental results, which illustrated the rationale for using M*. The results of this reported study will help facilitate the parameter design and performance analysis of a vibration isolation system with an inerter.

Application of Energy Method for Determining Loss Factor in Dynamic Systems with Hysteretic Damping

2014 ◽  
Vol 580-583 ◽  
pp. 2978-2982
Author(s):  
Vladimir Smirnov ◽  
Vladimir Mondrus
Keyword(s):  
Energy Method ◽  
Loss Factor ◽  
Seismic Isolation ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Experimental Investigations ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Hysteretic Damping ◽  
Different Types

The article studies the energy method for determining loss factor due to hysteretic damping in systems of vibration and seismic isolation. Typical measure of damping is, where φ is the phase angle between stress and strain sinusoids [1], or damping constant δ ( [2, 3]). Both of these parameters are acquired through experimental investigations for each type of boundary conditions or element’s cross section. Proposed energy method is capable of loss factor ψ determination for different types of beams based on only one experimental investigation. This method is used in the paper to determine the damping ratio of elastic element in vibration isolation system of precision equipment.

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