The time-delay coupling nonlinear effect in sky-hook control of vibration isolation systems using Magneto-Rheological Fluid dampers

2016 ◽  
Vol 30 (9) ◽  
pp. 4157-4166 ◽  
Author(s):  
Huijie Yu ◽  
Xiuting Sun ◽  
Jian Xu ◽  
Pei Zheng
Keyword(s):  
Time Delay ◽  
Nonlinear Effect ◽  
Vibration Isolation ◽  
Fluid Dampers ◽  
Isolation Systems ◽  
Magneto Rheological

Influence of Fractional Damping and Time Delay on Maxwell-Voigt Model for Vibration Isolation

2016 ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Model Parameters ◽  
Fractional Damping ◽  
Vibration Isolators ◽  
Multiple Parameters ◽  
Realistic Representation ◽  
Voigt Model ◽  
Isolation Systems

Models of vibration isolators are very commonly used for the design and analysis of isolation systems. Accurate isolator modeling is critical for a successful prediction of the dynamic characteristics of isolated systems. Isolators exhibit a complex behavior that depends on multiple parameters such as frequency, displacement amplitude, temperature and loading conditions. Therefore, it is important to choose a model that is accurate while adequately representing the relationships with relevant parameters. Recent literature has indicated some inherent advantages of fractional derivatives that can be exploited in the modeling of elastomeric isolators. Furthermore, time delay of damping is also seen to provide a realistic representation of damping. This paper examines the Maxwell-Voigt model with fractional damping and a time delay. This model is compared with the conventional Maxwell-Voigt model (without time delay or fractional damping) and the Voigt model in order to comprehend the influence of fractional damping and time delay on dynamic characteristics. Multiple simulations are performed after identifying model parameters from the data collected for a passive elastomeric isolator. The analysis results are compared and it is observed that the Voigt model is highly sensitive to fractional damping as well as time delay.

scholarly journals Line Spectrum Chaotification on QZS Systems with Time-Delay Control

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jing Zhang ◽  
Tao Tang ◽  
Wenhua Fang
Keyword(s):  
Comparative Analysis ◽  
Time Delay ◽  
Numerical Simulations ◽  
Vibration Isolation ◽  
Line Spectrum ◽  
New Approach ◽  
Time Delay Control ◽  
Control Gain ◽  
Delay Control ◽  
Isolation Systems

Chaotification can be employed to weaken or eliminate the feature of line spectra of waterborne noise. The efficiency of this method lies on the use of small control. The analysis reveals that the critical control gain depends on the stiffness of vibration isolation systems. Thus, an isolation raft system based on quasi-zero-stiffness (QZS) property is proposed for line spectrum chaotification. A nonlinear time-delay controller is derived accordingly. Comparative analysis shows that the new approach allows much smaller control, and the intensity of line spectra is further reduced. Numerical simulations also indicate other advantages with the introduction of QZS system into chaotification.

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.

A Variable Stiffness Vibration Isolation System Based on Magneto-Rheological Elastomer

2012 ◽  
Vol 452-453 ◽  
pp. 659-662
Author(s):  
Wei Wang ◽  
Yi Min Deng
Keyword(s):  
Shear Modulus ◽  
Vibration Isolation ◽  
Variable Stiffness ◽  
Control Area ◽  
Frequency Range ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Magneto Rheological ◽  
Conventional Type

Vibration isolation is a most widely used vibration protection method.The stiffness of vibration isolators in existing conventional type of vibration isolation system is usually of fixed value. This limits the system in exhibiting its vibration isolation effect in that, it has poor results for lower frequency vibration, especially for resonance frequency. Magneto-rheological elastomer is a new branch of Magneto-rheological materials. It’s an intelligent materials in that it’s shear modulus can be controlled by a magnetic field. It has wide application prospects in the vibration control area. This paper proposes using adjustable stiffness of magneto-rheological elastomer vibration isolation in vibration isolation system. By changing the current of vibration isolators coil to control the shear modulus of magneto-rheological elastomer, it can adjust the stiffness of the isolation system, making the system obtain wider vibration isolation frequency range. By exploying SimuLink software to analyze the vibration isolation system, it is found that such a design is effective and applicable.

Structural analysis of the trajectories of random processes formed in non-linear vibration isolation systems

2021 ◽  
Author(s):  
A.S. Gusev ◽  
L.V. Zinchenko ◽  
S.A. Starodubtseva
Keyword(s):  
Structural Analysis ◽  
Vibration Isolation ◽  
Fundamental Principle ◽  
Statistical Dependence ◽  
Absolute Maximum ◽  
Time Interval ◽  
Apparent Lack ◽  
The Road ◽  
Isolation Systems ◽  
Non Gaussian

When designing technical structures, the safety of their elements is a fundamental principle. This highlights the significance of the proposed solution to the structural analysis of the trajectories of non-Gaussian stationary processes. The solution aims to acquire source data for calculating the stress-strength reliability of structural elements operating under random loads. We analyze an approach that makes it possible to account for the statistical dependence between processes and their derivatives, despite the apparent lack of correlation between them. The considered approach can be utilized in the design of vibration protection of transport vehicles to calculate the probability of a shock absorber breakdown, the probability of loss of the road-wheel contact, etc. The operation reliability of such systems is defined as the probability that the absolute maximum of the process does not exceed the specified standard level during a certain time interval. The article presents the reliability calculation using structural analysis on the example of a one-dimensional stochastic system.

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.

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