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

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.

Design of a Miniaturized Pneumatic Vibration Isolator With High-Static-Low-Dynamic Stiffness

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Yuhu Shan ◽  
Wenjiang Wu ◽  
Xuedong Chen
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Structure Design ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Load Bearing Capacity ◽  
Compact Structure ◽  
Chamber Volume ◽  
Isolation Systems ◽  
Magnetic Rings

In the ultraprecision vibration isolation systems, it is desirable for the isolator to have a larger load bearing capacity and a broader isolation bandwidth simultaneously. Generally, pneumatic spring can bear large load and achieve relatively low natural frequency by enlarging its chamber volume. However, the oversized isolator is inconvenient to use and might cause instability. To reduce the size, a miniaturized pneumatic vibration isolator (MPVI) with high-static-low-dynamic stiffness (HSLDS) is developed in this paper. The volume of proposed isolator is minimized by a compact structure design that combines two magnetic rings in parallel with the pneumatic spring. The two magnetic rings are arranged in the repulsive configuration and can be mounted into the chamber to provide the negative stiffness. Then dynamic model of the developed MPVI is built and the isolation performances are analyzed. Finally, experiments on the isolator with and without the magnetic rings are conducted. The final experimental results are consistent with the dynamical model and verify the effectiveness of the developed vibration isolator.

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.

scholarly journals Implementation of the KDamper concept using disc springs

2018 ◽  
Vol 38 (1) ◽  
pp. 168-186
Author(s):  
Ioannis E Sapountzakis ◽  
Pavlos G Tranakidis ◽  
Ioannis A Antoniadis
Keyword(s):  
Structural Design ◽  
Vibration Isolation ◽  
Short Review ◽  
Optimal Combination ◽  
Negative Stiffness ◽  
External Excitation ◽  
Main Concept ◽  
Initial Displacement ◽  
Passive Vibration Isolation ◽  
Selection Of

The KDamper is a novel passive vibration isolation and damping concept, based essentially on the optimal combination of appropriate stiffness elements, which include a negative stiffness element. In this paper, after a short review of the optimal design and the selection of the parameters of the KDamper, the main concept focuses on the implementation of the negative stiffness elements with a set of Belleville (disc) springs. The major benefits of the proposed structure are the size and the robustness of the structure. The theory and the design process of the disc springs are presented thoroughly, as well as of the spiral springs with ground ends, along with an initial structural design. Simulation results from three different case scenarios are demonstrated; for an initial displacement, an initial velocity and an external excitation. The results obtained from the simulations show very satisfactory behavior.

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