Force and displacement transmissibility of a quasi-zero stiffness vibration isolator with geometric nonlinear damping

Generalized geometric nonlinear damping based on the viscous damper with a non-negative velocity exponent is proposed to improve the isolation performance of a quasi-zero stiffness (QZS) vibration isolator in this paper. Firstly, the generalized geometric nonlinear damping characteristic is derived. Then, the amplitude-frequency responses of the QZS vibration isolator under force and base excitations are obtained, respectively, using the averaging method. Parametric analysis of the force and displacement transmissibility is conducted subsequently. At last, two phenomena are explained from the viewpoint of the equivalent damping ratio. The results show that decreasing the velocity exponent of the horizontal damper is beneficial to reduce the force transmissibility in the resonant region. For the case of base excitation, it is beneficial to select a smaller velocity exponent only when the nonlinear damping ratio is relatively large.

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Research and Analysis of Quasi-Zero-Stiffness Isolator with Geometric Nonlinear Damping

Shock and Vibration ◽

10.1155/2017/6719054 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Qingguo Meng ◽

Xuefeng Yang ◽

Wei Li ◽

En Lu ◽

Lianchao Sheng

Keyword(s):

Vibration Isolation ◽

Low Frequency ◽

Harmonic Balance Method ◽

Nonlinear Damping ◽

Vibration Isolator ◽

Rehabilitation Robots ◽

Geometric Nonlinear ◽

Low Frequency Vibration ◽

Linear Spring ◽

The Relationship

This paper presents a novel quasi-zero-stiffness (QZS) isolator designed by combining a tension spring with a vertical linear spring. In order to improve the performance of low-frequency vibration isolation, geometric nonlinear damping is proposed and applied to a quasi-zero-stiffness (QZS) vibration isolator. Through the study of static characteristics first, the relationship between force displacement and stiffness displacement of the vibration isolation mechanism is established; it is concluded that the parameters of the mechanism have the characteristics of quasi-zero stiffness at the equilibrium position. The solutions of the QZS system are obtained based on the harmonic balance method (HBM). Then, the force transmissibility of the QZS vibration isolator is analyzed. And the results indicate that increasing the nonlinear damping can effectively suppress the transmissibility compared with the nonlinear damping system. Finally, this system is innovative for low-frequency vibration isolation of rehabilitation robots and other applications.

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Comparison of Linear and Nonlinear Damping Effects on a Ring Vibration Isolator

Nonlinear Dynamics and Control ◽

10.1007/978-3-030-34747-5_2 ◽

2020 ◽

pp. 13-22

Author(s):

Ze-Qi Lu ◽

Dong-Hao Gu ◽

Ye-Wei Zhang ◽

Hu Ding ◽

Walter Lacarbonara ◽

...

Keyword(s):

Nonlinear Damping ◽

Vibration Isolator ◽

Linear And Nonlinear ◽

Damping Effects

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Nonlinear Vibration Analysis of Viscoelastic Isolator

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.160.140 ◽

2012 ◽

Vol 160 ◽

pp. 140-144

Author(s):

Chao Zhou ◽

Cai Mao Zhong

Keyword(s):

Dynamic Response ◽

Fractional Derivative ◽

Nonlinear Dynamic ◽

Harmonic Balance Method ◽

Nonlinear Damping ◽

Vibration Isolator ◽

Response Characteristics ◽

Nonlinear Dynamic Equation ◽

The Stability ◽

Stiffness And Damping

Research on nonlinear dynamic response of passive vibration isolator, which was excited by foundation vibration and isolated by viscoelastic material was done. Nonlinear stiffness was expressed by the cubic polynomial function of deformation and nonlinear damping was characterized by viscoelastic fractional derivative operator. Then the fractional derivative nonlinear dynamic equation of passive vibration isolator was established. The dynamic response characteristics were analyzed by harmonic balance method and the frequency response equation and amplitude-frequency curve were obtained, and furthermore, the influence of nonlinearity on system was analyzed. Finally, the stability and the stable interval of the periodic solution were argued by the Floquet theory. The result s indicates that the proposed equation can precisely describe the dynamic characteristics of viscoelastic vibration isolator. The ignorance of nonlinearity of stiffness and damping will result in obvious error. The proposed method provides theoretic reference for design of viscoelastic isolator and the evaluation of its effect.

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Study on the force transmissibility of vibration isolators with geometric nonlinear damping

Nonlinear Dynamics ◽

10.1007/s11071-013-1027-0 ◽

2013 ◽

Vol 74 (4) ◽

pp. 1103-1112 ◽

Cited By ~ 23

Author(s):

Jingya Sun ◽

Xiuchang Huang ◽

Xingtian Liu ◽

Feng Xiao ◽

Hongxing Hua

Keyword(s):

Nonlinear Damping ◽

Vibration Isolators ◽

Geometric Nonlinear ◽

Force Transmissibility

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A Study of a Pendulum-Like Vibration Isolator With Quasi-Zero-Stiffness

10.1115/detc2021-70184 ◽

2021 ◽

Author(s):

Yishen Tian ◽

Dengqing Cao ◽

Yan Wang

Keyword(s):

Harmonic Balance ◽

Geometric Nonlinearity ◽

Harmonic Balance Method ◽

The Novel ◽

Vibration Isolator ◽

Frequency Range ◽

Jump Phenomenon ◽

Isolation Performance ◽

Force And Displacement Transmissibility ◽

Better Than

Abstract This article introduces a pendulum element to a 3-spring vibration isolator to achieve a high-static-low-dynamic (HSLD) stiffness or even quasi-zero stiffness (QZS) around the equilibrium position. Numerical simulation is given and the harmonic balance method (HBM) is used to obtain time responses for analysis. Effects of different parameters on the isolation performance are studied and summarized. Approximation force and displacement transmissibility of the system are calculated to evaluate the isolation performance. Comparisons are made with those of an equivalent linear isolator and the typical 1 degree-of-freedom (DOF) QZS isolator. Results show that the novel vibration isolator performs better than existing isolators under selected parameters. The left bent backbone of the novel isolator demonstrates evident softening geometric nonlinearity. Therefore, it achieves a wider frequency range of isolation than the linear 1DOF isolator and typical 3-spring QZS isolator. Moreover, the transmissibility of the novel isolator is smaller at higher frequencies as the jump phenomenon occurs on the left.

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The Damping Characteristics of Vibration Isolators Used in Gas Turbines

Journal of Mechanical Engineering Science ◽

10.1243/jmes_jour_1977_019_055_02 ◽

1977 ◽

Vol 19 (6) ◽

pp. 271-277 ◽

Cited By ~ 9

Author(s):

R. Holmes

Keyword(s):

Gas Turbines ◽

Journal Bearing ◽

Nonlinear Damping ◽

Common Type ◽

Squeeze Film ◽

Vibration Isolator ◽

Vibration Isolators ◽

Damping Coefficients ◽

Damping Characteristics ◽

Linear Damping

The linear and nonlinear damping performance of a common type of gas-turbine vibration isolator, consisting of a squeeze-film journal bearing in parallel with a linear retainer spring, is computed and used to prescribe limits to the use of linear damping coefficients.

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An Asymmetric Quasi-zero Stiffness Vibration Isolator with Long Stroke and Large Bearing Capacity

10.21203/rs.3.rs-730417/v1 ◽

2021 ◽

Author(s):

Xinghua Zhou ◽

Dingxuan Zhao ◽

Xiao Sun ◽

Xiao Yang ◽

Jianhai Zhang ◽

...

Keyword(s):

Bearing Capacity ◽

Vibration Isolation ◽

Geometrical Nonlinearity ◽

Harmonic Balance Method ◽

Nonlinear Damping ◽

Vibration Isolator ◽

Plate Spring ◽

Supporting Force ◽

Vibration Isolation Performance ◽

Isolation Performance

Abstract A novel passive asymmetric quasi-zero stiffness vibration isolator (AQZS-VI) comprising two linear springs acting in parallel with one negative stiffness element (NSE) is proposed, of which the NSE is mainly constructed by the combination of cantilever plate spring and L-shaped lever (CPS-LSL). The static model of the isolator is deduced considering the geometrical nonlinearity of the NSE and the bending deformation of plate spring. The nonlinear stiffness properties of the CPS-LSL and the AQZS-VI, as well as the nonlinear damping properties of the AQZS-VI are discussed. The absolute displacement transmissibility of the AQZS-VI under base displacement excitation is obtained using Harmonic Balance Method, and the effects of different excitation amplitudes and damping factors on the vibration isolation performance are analyzed. Better than other quasi-zero stiffness vibration isolators (QZS-VI) whose NSEs do not provide supporting force at zero stiffness point, the NSE of the AQZS-VI provides more supporting force than the parallel connected linear springs, which is very beneficial for improving the bearing capacity of the isolator. Compared with a typical symmetric QZS-VI with same damping property, the AQZS-VI has longer stroke with low stiffness and lower peak value of displacement transmissibility. The prototype experiments indicate that the AQZS-VI outperforms the linear counterpart with much smaller starting frequency of vibration isolation and lower displacement transmissibility. The proposed AQZS-VI has great potential for applying in various engineering practices with superior vibration isolation performance.

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