A Six Degrees-of-Freedom Vibration Isolation Platform Supported by a Hexapod of Quasi-Zero-Stiffness Struts

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Jiaxi Zhou ◽  
Kai Wang ◽  
Daolin Xu ◽  
Huajiang Ouyang ◽  
Yingli Li
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Permanent Magnets ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Dynamic Responses ◽  
Six Degrees Of Freedom ◽  
Low Frequency Vibration ◽  
Force Moment ◽  
Vibration Isolation Performance

A platform supported by a hexapod of quasi-zero-stiffness (QZS) struts is proposed to provide a solution for low-frequency vibration isolation in six degrees-of-freedom (6DOFs). The QZS strut is developed by combining a pair of mutually repelling permanent magnets in parallel connection with a coil spring. Dynamic analysis of the 6DOFs QZS platform is carried out to obtain dynamic responses by using the harmonic balance method, and the vibration isolation performance in each DOF is evaluated in terms of force/moment transmissibility, which indicates that the QZS platform perform a good function of low-frequency vibration isolation within broad bandwidth, and has notable advantages over its linear counterpart in all 6DOFs.

Harnessing the Quasi-Zero Stiffness From Fluidic Origami for Low Frequency Vibration Isolation

2017 ◽  
Author(s):  
Sahand Sadeghi ◽  
Suyi Li
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Design Parameters ◽  
Base Excitation ◽  
Design Guideline ◽  
Low Frequencies ◽  
Cellular Solid ◽  
Low Frequency Vibration ◽  
Internal Volume

This research investigates a quasi-zero stiffness (QZS) property from the pressurized fluidic origami cellular solid, and examines how this QZS property can be harnessed for low-frequency base excitation isolation. The QZS property originates from the nonlinear geometric relations between folding and internal volume change, and it is directly correlated to the design parameters of the constituent Miura-Ori sheets. Two different structures are studied to obtain a design guideline for achieving QZS: one is identical stacked Miura-Ori sheets (ismo) and the other is non-identical stacked Miura-Ori sheets (nismo). Further dynamic analyses based on numerical simulation and harmonic balance method, indicate that the QZS from pressurized fluidic origami can achieve effective base excitation isolation at low frequencies. Results of this study can become the foundation of origami-inspired metamaterials and metastructures with embedded dynamic functionalities.

Application of dynamic vibration absorbers in designing a vibration isolation track at low-frequency domain

2017 ◽  
Vol 231 (5) ◽  
pp. 546-557 ◽  
Author(s):  
Shengyang Zhu ◽  
Jizhong Yang ◽  
Chengbiao Cai ◽  
Zili Pan ◽  
Wanming Zhai
Keyword(s):  
Vibration Isolation ◽  
Parametric Design ◽  
Low Frequency ◽  
Design Parameters ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Low Frequency Vibration ◽  
Dynamic Vibration Absorbers ◽  
Vibration Isolation Performance ◽  
Isolation Performance

This paper aims to develop a low-frequency vibration isolation track based on passive vibration isolation theory and vehicle–track interaction analysis. First, a preliminary low-frequency vibration isolation track is proposed by attaching multiple dynamic vibration absorbers to a discontinuous floating slab track, and the optimal design parameters of the multidynamic vibration absorber are determined by searching the minimum values of two assessment functions. Further, a three-dimensional coupled dynamic model of a metro vehicle and the low-frequency vibration isolation track is established by using Ansys Parametric Design Language, where the equations of motion of the vehicle subsystem and the wheel–rail contact calculations are incorporated in the software Ansys using the Ansys Parametric Design Language, and the low-frequency vibration isolation track subsystem is directly created by using common elements in Ansys. The vibration isolation performance of the preliminary low-frequency vibration isolation track with multidynamic vibration absorber is investigated under harmonic load and vehicle dynamic load, respectively. Results show that the slab acceleration and supporting force are significantly reduced at low frequencies of 10–20 Hz compared with those of the traditional floating slab tracks. Finally, an improved low-frequency vibration isolation track is developed for actual manufacturing and practical application, and simulations show that the improved low-frequency vibration isolation track exhibits a more robust vibration isolation performance even if optimal design parameters have variations due to manufacturing errors or material deterioration.

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

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
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.

scholarly journals Post-Buckling Spring Vibration Isolator Using Silicone Gel Column: A Theoretical and Experimental Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10559
Author(s):  
Ji-Hou Yang ◽  
Xiao-Dong Yang ◽  
Qing-Kai Han ◽  
Jin-Guo Liu
Keyword(s):  
Vibration Isolation ◽  
Elliptic Integral ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Low Frequency ◽  
Harmonic Balance Method ◽  
Vibration Isolator ◽  
Silicone Gel ◽  
Low Frequency Vibration ◽  
Post Buckling

Based on the design of a post-buckling silicone gel column (SGC), a novel type of low-frequency vibration isolator is presented, and the vibration isolation performance of this isolator is studied by combining theoretical analysis and experimental verification. The stiffness characteristics of the post-buckling SGC are derived, and its recovery force curves with different parameters are analyzed using two kinds of elliptic integral functions. Displacement transmissibility is formulated using harmonic balance method (HBM), and the influences of the excitation amplitude, damping ratio, SGC section diameter, and Young’s modulus are discussed in terms of the transmissibility. The performance of the SGC system is verified through a series of experimental studies based on the developed experimental prototype. The result shows that the proposed post-buckling spring vibration isolator has a good vibration isolation effect, especially in the low-frequency domain, which may provide a feasible novel design idea for a low-frequency vibration isolator.

Low Frequency Vibration Isolation Through an Active-on-Active Approach: Coupling Effects

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Qiao Sun ◽  
Robert A. Wolkow ◽  
Mark Salomons
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Noise Cancellation ◽  
Frequency Noise ◽  
Active Stage ◽  
Coupling Effects ◽  
Active Approach ◽  
Low Frequency Vibration ◽  
Wide Range ◽  
Coupling Characteristics

The extreme sensitivity of a scanning probe microscope demands an exceptional noise cancellation device that could effectively cut off a wide range of vibration noise. Existing commercial devices, although excellent in canceling high frequency noise, commonly leave low frequency vibration unattenuated. We design an add-on active stage that can function together with a standalone existing active stage. The objective is to provide a higher level of noise cancellation by lowering the overall system cut-off frequency. This study is concerned with the theoretical aspects of the coupling characteristics involved in stacking independently designed stages together to form a two-stage isolator. Whether an add-on stage would pose a stability threat to the existing stage needs to be addressed. In addition, we explore the use of coupling effects to optimize the performance of the overall system.

On vibration isolation of sandwich plate with periodic hollow tube core

2017 ◽  
Vol 21 (3) ◽  
pp. 1119-1132 ◽  
Author(s):  
Gui-Lan Yu ◽  
Hong-Wei Miao
Keyword(s):  
Vibration Isolation ◽  
Sandwich Plate ◽  
Experimental Studies ◽  
Low Frequency ◽  
Dispersion Relations ◽  
Frequency Responses ◽  
Vibration Attenuation ◽  
Potential Applications ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolation performance of a PC sandwich plate with periodic hollow tube core is investigated experimentally and numerically. The experiment results reveal that there exist vibration attenuation zones in acceleration frequency responses which can be improved by increasing the number of periods or tuning some structure parameters. The presence of soft fillers shifts the attenuation zone to lower frequencies and enhances the capability of vibration isolation to some extent. Dispersion relations and acceleration frequency responses are calculated by finite element method using COMSOL MULTIPHYSICS. The attenuation zones obtained by experiments fit well with that by simulations, and both are consistent with the band gap in dispersion relations. The numerical and experimental studies in the present paper show that this PC sandwich plate exhibits a good performance on vibration isolation in low frequency ranges, which will provide some useful references for relevant research and potential applications in vibration propagation manipulations.

On the Effects of Mistuning a Force-Excited System Containing a Quasi-Zero-Stiffness Vibration Isolator

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Ali Abolfathi ◽  
M. J. Brennan ◽  
T. P. Waters ◽  
B. Tang
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Vibration Isolators ◽  
Zero Dynamic ◽  
Low Frequency Vibration ◽  
Excited System ◽  
Better Than

Nonlinear isolators with high-static-low-dynamic-stiffness have received considerable attention in the recent literature due to their performance benefits compared to linear vibration isolators. A quasi-zero-stiffness (QZS) isolator is a particular case of this type of isolator, which has a zero dynamic stiffness at the static equilibrium position. These types of isolators can be used to achieve very low frequency vibration isolation, but a drawback is that they have purely hardening stiffness behavior. If something occurs to destroy the symmetry of the system, for example, by an additional static load being applied to the isolator during operation, or by the incorrect mass being suspended on the isolator, then the isolator behavior will change dramatically. The question is whether this will be detrimental to the performance of the isolator and this is addressed in this paper. The analysis in this paper shows that although the asymmetry will degrade the performance of the isolator compared to the perfectly tuned case, it will still perform better than the corresponding linear isolator provided that the amplitude of excitation is not too large.

Sign in / Sign up

Export Citation Format

Share Document