Controllable electromagnetic negative stiffness spring for vibration isolator: Design, analyses and experimental verification

2020 ◽  
pp. 1-22
Author(s):  
Kai Meng ◽  
Yong Gu ◽  
Jianhui Ma ◽  
Xidong Liu ◽  
Xiangqian Geng ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Permanent Magnets ◽  
Structural Parameters ◽  
Negative Stiffness ◽  
Axial Stiffness ◽  
Isolation System ◽  
Exciting Current ◽  
Circular Current ◽  
Design Analyses ◽  
The Mathematical Model

In this study, a novel negative stiffness spring is developed. The developed spring possesses the characteristics of the controllable stiffness and can be employed in vibration isolation system with a low resonance frequency. The controllable electromagnetic negative stiffness spring (CENSS) is obtained by the coaxial permanent magnets (PMs) and the circular current-carrying coils. The stiffness control is accomplished by changing the current in the coils. Furthermore, the mathematical model of CENSS is established, based on the filament method. According to the model, the relationship between the exciting current and the axial stiffness is obtained. Moreover, the influence of the structural parameters of CENSS on the magnetic force and the stiffness is analyzed. The results demonstrate that the thickness of PMs and the coils have the ability to adjust the range of the negative stiffness. Finally, performance experimental study of CENSS in the stiffness domain is carried out under different exciting currents and thicknesses. The experimental results have shown a good agreement with the model. It demonstrates that the performance of negative stiffness in CENSS can be controlled efficiently by the exciting current and optimized by the thickness.

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.

Modeling and Dynamics of Magnetically Repulsive Negative Stiffness Permanent Magnetic Array for Precision Air/Magnetic Composite Vibration Isolation

2021 ◽  
Author(s):  
Yamin Zhao ◽  
Junning Cui ◽  
Limin Zou ◽  
Zhongyi Cheng
Keyword(s):  
Vibration Isolation ◽  
Permanent Magnets ◽  
Structural Parameters ◽  
Low Frequency ◽  
Vertical Direction ◽  
High Amplitude ◽  
Negative Stiffness ◽  
Magnetic Composite ◽  
Experimental Systems ◽  
Vibration Transmissibility

To reduce the natural frequency of air isolators and realize low or ultra-low frequency air/magnetic composite vibration isolation with large payloads, a magnetically repulsive negative stiffness permanent magnetic array (MRNSPMA) is proposed. Specifically, we utilize cuboidal permanent magnets to form a spatial array that is mechanically repulsive in the horizontal direction and structurally parallel in the vertical direction. The superiority of MRNSPMA in achieving high amplitude negative stiffness is verified. Furthermore, the effects of structural parameters on vibration transmissibility under the base and force excitations are investigated with the introduction of MRNSPMA. The displacement transmissibility, the force transmissibility and the frequency corresponding to the peak transmissibility are significantly reduced, validating the promise of MRNSPMA for improving the isolation performance of cutting-edge scientific experimental systems and facilities.

scholarly journals Electromagnetic and Mechanical Characteristics Analysis of a Flat-Type Vertical-Gap Passive Magnetic Levitation Vibration Isolator

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Baoquan Kou ◽  
Yiheng Zhou ◽  
Xiaobao Yang ◽  
Feng Xing ◽  
He Zhang
Keyword(s):  
Vibration Isolation ◽  
Mechanical Characteristics ◽  
Magnetic Levitation ◽  
Structural Parameters ◽  
Force Density ◽  
Vibration Isolator ◽  
Isolation System ◽  
Flat Type ◽  
Characteristics Analysis ◽  
Vertical Gap

In this paper, we describe a flat-type vertical-gap passive magnetic levitation vibration isolator (FVPMLVI) for active vibration isolation system (AVIS). A dual-stator scheme and a special stator magnet array are adopted in the proposed FVPMLVI, which has the effect of decreasing its natural frequency, and this enhances the vibration isolation capability of the FVPMLVI. The structure, operating principle, analytical model, and electromagnetic and mechanical characteristics of the FVPMLVI are investigated. The relationship between the force characteristics (levitation force, horizontal force, force ripple, and force density) and major structural parameters (width and thickness of stator and mover magnets) is analyzed by finite element method. The experiment result is in good agreement with the theoretical analysis.

Modeling Electromagnetic Force and Axial-Stiffness for an Electromagnetic Negative-Stiffness Spring Toward Vibration Isolation

2019 ◽  
Vol 55 (3) ◽  
pp. 1-10 ◽  
Author(s):  
Yi Sun ◽  
Kai Meng ◽  
Shujin Yuan ◽  
Jinglei Zhao ◽  
Rongqing Xie ◽  
...  
Keyword(s):  
Electromagnetic Force ◽  
Vibration Isolation ◽  
Negative Stiffness ◽  
Axial Stiffness

Vibration Isolation in a Microgravity Environment

1993 ◽  
Vol 115 (4) ◽  
pp. 477-483
Author(s):  
R. M. Alexander ◽  
C. H. Gerhold ◽  
C. B. Atwood ◽  
J. F. Cordera
Keyword(s):  
Vibration Isolation ◽  
Center Of Mass ◽  
Space Station ◽  
Microgravity Environment ◽  
Isolation System ◽  
Air Jet ◽  
Surrounding Structure ◽  
Jet Control ◽  
Oscillatory Response ◽  
The Mathematical Model

Many in-space research experiments require the microgravity environment attainable near the center of mass of the proposed space station. Since dynamic disturbances to the surrounding structure may undermine an experiment’s validity, isolation of these experiments is imperative. This paper summarizes analytical and experimental work accomplished to develop an isolation system which allows the pay load to float freely within a prescribed boundary while being kept centered with forces generated by small jets of air. An experimental setup was designed and constructed to simulate the microgravity environment In the horizontal plane. Results demonstrate the air jet control system to be effective in managing payload oscillatory response. An analytical model was developed and verified by comparing predicted and measured payload response. The mathematical model is then used to investigate payload response to disturbances likely to be present in the space station.

scholarly journals Vibration Isolation System Using Negative Stiffness

2003 ◽  
Vol 46 (3) ◽  
pp. 807-812 ◽  
Author(s):  
Takeshi MIZUNO ◽  
Takefumi TOUMIYA ◽  
Masaya TAKASAKI
Keyword(s):  
Vibration Isolation ◽  
Negative Stiffness ◽  
Isolation System ◽  
Vibration Isolation System

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.

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