scholarly journals Dynamic Research on Low-Frequency Vibration Isolation Tables

2020 ◽  
Author(s):  
Mindaugas Jurevicius ◽  
Gintas Viselga ◽  
Vytautas Turla ◽  
Eugenijus Jurkonis ◽  
Ina Tetsman
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Dynamic Models ◽  
Low Frequency ◽  
Experimental Tests ◽  
Theoretical Research ◽  
Isolation System ◽  
Low Frequency Vibration ◽  
Resonance Frequencies ◽  
Isolation Systems

Abstract In the paper, an establishment of dynamic characteristics of tabletops of the newly-developed optical tables is being discussed upon. Low-frequency vibration isolation systems are reviewed. Theoretical and experimental tests have been performed. Dynamic models of an optical table on a vibrating platform at different excitations have been developed, the dynamic displacement and the resonance frequencies of the system have been established and vibration transmissibility curves have been presented. The obtained dynamic characteristics of the mechanical passive low-frequency vibration isolation system show that such a system is able to isolate the vibrations effectively. The results of the performed experimental tests confirm the data of the theoretical research.

scholarly journals Dynamic research on a low-frequency vibration isolation system of quasi-zero stiffness

2019 ◽  
Vol 38 (2) ◽  
pp. 684-691
Author(s):  
M Jurevicius ◽  
V Vekteris ◽  
G Viselga ◽  
V Turla ◽  
A Kilikevicius ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Acoustic Noise ◽  
Low Frequency ◽  
Experimental Tests ◽  
Theoretical Research ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Low Frequency Vibration ◽  
Conditioning Equipment

The paper describes an establishment of dynamic characteristics of the newly created passive mechanical system for isolation of low-frequency (0.7 Hz–50 Hz) vibrations. The many metrological means are sensitive to mechanical vibrations and acoustic noise of low frequency. Such may appear both outside and inside a building, i.e. may be caused by wind, heating, aeration, air conditioning equipment, moving vehicles and other. In the paper, description of the theoretical and experimental tests is provided. The obtained dynamic characteristics (transmissibilities) of the passive mechanical low-frequency vibration isolation system show that such a system is able to isolate vibrations effectively in the frequency range of 0.7 Hz–50 Hz. The results of the experimental tests support the results of the theoretical research.

Recent Advances in Quasi-Zero-Stiffness Vibration Isolation Systems

2013 ◽  
Vol 397-400 ◽  
pp. 295-303 ◽  
Author(s):  
Fu Niu ◽  
Ling Shuai Meng ◽  
Wen Juan Wu ◽  
Jing Gong Sun ◽  
Wei Hua Su ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Future Research ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Significant Development ◽  
Recent Advances ◽  
Low Frequency Vibration ◽  
Future Research Directions ◽  
Isolation Systems

The quasi-zero-stiffness vibration isolation system has witnessed significant development due to the pressing demands for low frequency and ultra-low frequency vibration isolation. In this study, the isolation theory and the characteristic of the quasi-zero-stiffness vibration isolation system are illustrated. Based on its implementation mechanics, a comprehensive assessment of recent advances of the quasi-zero-stiffness vibration isolation system is presented. The future research directions are finally prospected.

scholarly journals Investigation of the dynamic efficiency of complex passive low-frequency vibration isolation systems

2019 ◽  
Vol 38 (2) ◽  
pp. 608-614 ◽  
Author(s):  
M Jurevicius ◽  
V Vekteris ◽  
V Turla ◽  
A Kilikevicius ◽  
G Viselga
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Experimental Investigations ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Low Frequency Vibration ◽  
Vibrating Platform ◽  
Optical Table ◽  
Narrow Frequency Range ◽  
Isolation Systems

In this study, the theoretical and experimental investigations of the dynamics of complex passive low-frequency vibration systems are described. It is shown that a complex system consisting of a vibrating platform, an optical table and a vibration isolation system of quasi-zero stiffness loaded by a certain mass may isolate low-frequency vibrations in a narrow frequency range only. In another case, the system does not isolate vibrations; it even operates as an amplifier. The frequencies that ensure the top efficiency of the vibration damping system of quasi-zero stiffness were established.

scholarly journals Vibration Isolation Critical to Measuring Neuronal Patterns in the Brain

2009 ◽  
Vol 17 (3) ◽  
pp. 12-15
Author(s):  
David L. Platus
Keyword(s):  
Neuronal Activity ◽  
Vibration Isolation ◽  
Medical Center ◽  
Low Frequency ◽  
Vibration Isolators ◽  
Low Frequency Vibration ◽  
Conducting Research ◽  
Neuronal Patterns ◽  
Isolation Systems ◽  
The Brain

Researchers at Georgetown University's Department of Physiology and Biophysics use negative-stiffness vibration isolators to help measure micron-level patterns of neuronal activity in the mammalian neocortex. The research is shedding new light into brain sensory and motor processing functions relating to cardiac fibrillation and epilepsy.Isolating a laboratory's sensitive microscopy equipment against low-frequency vibration has become increasingly more vital to maintaining imaging quality and data integrity for neurobiology researches. Ever more frequently, laboratory researchers are discovering that conventional air tables and the more recent active (electronic) vibration isolation systems are not able to adequately cancel out the lower frequency perturbations derived from air conditioning systems, outside vehicular movements and ambulatory personnel. Such was the case with the Department of Physiology and Biophysics at Georgetown University Medical Center, where Professor Jian-Young Wu has been conducting research on waves of neuronal activity in the neocortex of the brain.

On the Performance of a Two-Stage Vibration Isolation System Which has Geometrically Nonlinear Stiffness

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Zeqi Lu ◽  
Tiejun Yang ◽  
Michael J. Brennan ◽  
Xinhui Li ◽  
Zhigang Liu
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Single Stage ◽  
Nonlinear Stiffness ◽  
Two Stage ◽  
Isolation System ◽  
Beneficial Effects ◽  
Isolation Systems ◽  
The Right

Linear single-stage vibration isolation systems have a limitation on their performance, which can be overcome passively by using linear two-stage isolations systems. It has been demonstrated by several researchers that linear single-stage isolation systems can be improved upon by using nonlinear stiffness elements, especially for low-frequency vibrations. In this paper, an investigation is conducted into whether the same improvements can be made to a linear two-stage isolation system using the same methodology for both force and base excitation. The benefits of incorporating geometric stiffness nonlinearity in both upper and lower stages are studied. It is found that there are beneficial effects of using nonlinearity in the stiffness in both stages for both types of excitation. Further, it is found that this nonlinearity causes the transmissibility at the lower resonance frequency to bend to the right, but the transmissibility at the higher resonance frequency is not affected in the same way. Generally, it is found that a nonlinear two-stage system has superior isolation performance compared to that of a linear two-stage isolator.

scholarly journals Modeling a Mechanical Molecular Spring Isolator with High-Static-Low-Dynamic-Stiffness Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhanyong Li ◽  
Qian Chen ◽  
Fengshou Gu ◽  
Andrew Ball
Keyword(s):  
Vibration Isolation ◽  
Dynamic Properties ◽  
Piecewise Linear ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Isolation System ◽  
Isolation Technique ◽  
Piston Cylinder ◽  
Low Frequency Vibration ◽  
Stiffness Model

A mechanical molecular spring isolator (MMSI) is proposed for the purpose of isolating the low-frequency vibration of a heavy payload. The MMSI is a passive vibration isolation technique mimicking molecular spring isolator characteristics of high-static-low-dynamic stiffness (HSLDS). An MMSI consists of a piston-cylinder container filled with the liquid and some hydraulic spring accumulators. The piston would support a lump of mass and be subjected to a specific external vibration excitation force. Those accumulators can get intercommunication by the liquid to produce the transformation from high static stiffness to low dynamic stiffness. The stiffness model of the MMSI with several identical accumulators is established based on the hydrostatic law. After that, some parameters that significantly influence the stiffness characteristics are studied. Results show that the stiffness property of this kind of MMSI demonstrates a piecewise linearity of three segments. It applies the averaging method to acquire amplitude-frequency and phase-frequency relationships of the piecewise linear vibration isolation system. An inevitable jump phenomenon may occur when the exciting force reaches the critical value. The vibration isolation performance is evaluated by energy transmissibility. Finally, an experimental prototype was designed to carry out quasi-static and dynamic experiments to verify the stiffness model and the dynamic properties as an HSLDS vibration isolator.

Vibration Isolation Characteristics of Euler Strut Spring Used in Low Frequency Vibration Isolation System

2012 ◽  
Vol 248 ◽  
pp. 475-480
Author(s):  
Guan Jun Zhang ◽  
Xiang Zhu ◽  
Ran Xu ◽  
Tian Yun Li
Keyword(s):  
Vibration Isolation ◽  
Structural Parameters ◽  
Low Frequency ◽  
Resonant Frequencies ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Low Frequency Vibration ◽  
Steel Material ◽  
Internal Resonant ◽  
Spring Maximum

Recently, the Euler strut is used as the supporting spring in the low frequency isolation. An Euler spring is a column or strut of steel material which is compressed elastically beyond its buckling load, which makes the ratio of the isolated mass to the mass of the supporting spring maximum, and greatly increasing the internal resonant frequencies of the isolator. In this research, the unique mechanical properties and the expressions of the displacement transmissibility of the Euler strut are deduced. The influences of structural parameters of the strut on the stiffness and vibration isolation characteristics are investigated in detail. The results show that the Euler strut has the potential in low frequency vibration isolation, and the length and breadth of the strut can influence the stiffness, transmissibility and critical loading mass respectively.

scholarly journals RESEARCH ON VIBRATION ISOLATION SYSTEMS USED IN LASER AND NANOTECHNOLOGIES / VIBROIZOLIACINIŲ SISTEMŲ, NAUDOJAMŲ LAZERINĖSE IR NANOTECHNOLOGIJOSE, TYRIMAI

2013 ◽  
Vol 6 (4) ◽  
pp. 559-563
Author(s):  
Justinas Kuncė ◽  
Mindaugas Jurevičius
Keyword(s):  
Vibration Isolation ◽  
Composite System ◽  
Experimental Tests ◽  
Negative Stiffness ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Transmissibility ◽  
Optical Table ◽  
Air Table ◽  
Isolation Systems

The paper discusses the efficiency of a vibration isolation system made of the optical table and two negative-stiffness tables and considers excitation referring to harmonic and nonharmonic methods in the frequency range of 0,2–110 Hz. The article reviews the types and sources of vibrations and types of vibration isolation systems, including those of negative-stiffness. The paper also presents the methodology of experimental tests and proposes research on vibration transmissibility. A composite system consisting of two vibration isolation table having negative stiffness and an air table has been tested. The results and conclusions of experimental analysis are suggested at the end of the article. Santrauka Nagrinėjama vibroizoliacinės sistemos, sudarytos iš optinio stalo ir dviejų neigiamo standumo staliukų, efektyvumas žadinant harmoniniu ir neharmoniniais būdais 0,2–110 Hz diapazone. Aprašyta eksperimentinių tyrimų atlikimo metodika ir atlikti virpesių perduodamumo tyrimai. Ištirta sudėtinė sistema, sudaryta iš dviejų neigiamo standumo virpesių izoliavimo staliukų ir optinio stalo. Nustatytos vibracijų slopinimo charakteristikos. Pateikti eksperimentų metu gauti rezultatai ir išvados.

scholarly journals Dynamics and Stability of Magnetic-air Hybrid Quasi-zero Stiffness Vibration Isolation System

2021 ◽  
Author(s):  
Youliang Jiang ◽  
Chunsheng Song ◽  
Xin Ma ◽  
Han Wu ◽  
Zhihui Mai
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Isolation Effect ◽  
Machining Accuracy ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Factors Affecting ◽  
Low Frequency Vibration ◽  
Nonlinear Mechanical ◽  
The Stability

Abstract With the improvement of machining accuracy, external low frequency vibration has become one of the most important factors affecting the performance of equipment. The theory of quasi-zero stiffness vibration isolation shows favorable low frequency vibration isolation effect. Based on our previous research on the structure of magnetic-air hybrid quasi-zero stiffness vibration isolation system, the nonlinear mechanical expression of positive and negative stiffness structure has been analyzed in this paper, to improve application of the system and provide a theoretical basis for sequential studies of active control. To analyze the judgement criterion of the quasi-zero stiffness, an accurate mechanical model was first established. Then, the dynamical model based on external low frequency vibration was developed, to investigate the stability and natural frequency and deduce the amplitude frequency characteristics and displacement transfer rate. Finally, we carried out simulation and experimental analysis to verify the stiffness of high static and low dynamic and the low frequency vibration isolation effect of the vibration isolation system.

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