scholarly journals Theoretical Analysis and Numerical Simulation of Resonances and Stability of a Piecewise Linear-Nonlinear Vibration Isolation System

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
X. Gao ◽  
Q. Chen
Keyword(s):  
Vibration Isolation ◽  
Theoretical Study ◽  
Piecewise Linear ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Weakly Nonlinear ◽  
The Stability ◽  
Subharmonic Resonances ◽  
Good Agreement

A methodology is presented to study the resonance and stability for a single-degree-of-freedom (SDOF) system with a piecewise linear-nonlinear stiffness term (i.e., one piece is linear and the other is weakly nonlinear). Firstly, the exact response of the linear governing equation is obtained, and a modified perturbation method is applied to finding the approximate solution of the weakly nonlinear equation. Then, the primary and 1/2 subharmonic resonances are obtained by imposing continuity conditions and periodicity conditions. Furthermore, Jacobian matrix is derived to investigate the stability of resonance responses. Finally, the results of theoretical study are compared with numerical results, and a good agreement is observed.

Development of Six Degrees of Freedom Vibration Isolation System for Microgravity Environment

1995 ◽  
Author(s):  
Toshiyuki Suzuki ◽  
Koji Tanida ◽  
Akira Tanji ◽  
Koichi Okubo
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Parabolic Flight ◽  
Microgravity Environment ◽  
External Disturbances ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Active Vibration ◽  
Good Agreement

Abstract An active vibration isolation system, under development for use in microgravity environment, provides electromagnetic suspension by means of voice coils arranged in pairs to control the translational and rotational movements of the payload, three pairs of which cover the three axes to ensure control of payload movement in all six degrees of freedom. A series of tests performed on this system in microgravity environment created by parabolic flight proved that external disturbances in frequencies above 0.1 Hz were effectively reduced by applying the system. Also, good agreement was obtained between the measured performance and results of numerical simulation.

scholarly journals An inerter-based active vibration isolation system

2018 ◽  
Vol 148 ◽  
pp. 11001
Author(s):  
Neven Alujević ◽  
Damjan Čakmak ◽  
Hinko Wolf ◽  
Marko Jokić
Keyword(s):  
Kinetic Energy ◽  
Control Systems ◽  
Vibration Isolation ◽  
Theoretical Study ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Dynamic Excitation ◽  
Active Vibration ◽  
Two Degree Of Freedom ◽  
Active Vibration Isolation

This paper presents a theoretical study on passive and active vibration isolation schemes using inerter elements in a two degree of freedom (DOF) mechanical system. The aim of the work is to discuss basic capabilities and limitations of the vibration control systems at hand using simple and physically transparent models. Broad frequency band dynamic excitation of the source DOF is assumed. The purpose of the isolator system is to prevent vibration transmission to the receiving DOF. The frequency averaged kinetic energy of the receiving mass is used as the metric for vibration isolation quality. It is shown that the use of inerter in the passive and active vibration isolation schemes considered enhances the isolation effect.

A Modular-Type Three-Axis Vibration Isolation System Using Negative Stiffness

2010 ◽  
Author(s):  
Md. Emdadul Hoque ◽  
Takeshi Mizuno ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Negative Stiffness ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Single Degree ◽  
In Series ◽  
Isolation Systems

A vibration isolation system is presented in this paper which is developed by the combination of multiple vibration isolation modules. Each module is fabricated by connecting a positive stiffness suspension in series with a negative stiffness suspension. Each vibration isolation module can be considered as a self-sufficient single-degree-of-freedom vibration isolation system. 3-DOF vibration isolation system can be developed by combining three modules. As the number of motions to be controlled and the number of actuators are equal, there is no redundancy in actuators in such vibration isolation systems. Experimental results are presented to verify the proposed concept of the development of MDOF vibration isolation system using vibration isolation modules.

Vibration Mitigation Using Passive Active Tunable (PAT) System: Experimental Aspects

2006 ◽  
Vol 129 (2) ◽  
pp. 209-216
Author(s):  
N. Sarigul-Klijn ◽  
I. Lopez ◽  
M. Sarigul-Klijn ◽  
D. Karnopp
Keyword(s):  
Vibration Isolation ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Dependent Behavior ◽  
Acceleration Amplitude ◽  
Damper Design ◽  
Motion Characteristics ◽  
Pat System ◽  
Different Levels

The objective of this paper is to test and model a single-degree-of-freedom vibration isolation system with a magnetorheological (MR) foam damper under harmonic and random excitations. The results of this research are valuable for understanding the characteristics of the MR foam damper and include the experimental design and results of vibration mitigations for frequency ranges up to 2000Hz. Transmissibility and acceleration hysteresis experiments of the MR foam damper system with different levels of input current are discussed. A simple damper design that eliminates many of the constraints normally associated with fluid filled devices is presented. Constitutive equations of the Bouc–Wen model are used to validate and characterize the MR foam damper. The motion characteristics of the MR foam damper are studied. Experimental results reveal that the mechanical behavior of the MR foam damper is nonlinear and that the field-dependent behavior of MR foam damper is associated with the applied frequency and acceleration amplitude. Experiments demonstrate MR foam damper works well in controlling vibrations and can be controlled and tuned for specific applications.

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.

An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

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