Vibration Analysis of Nonlinear Isolator’s Characteristics by ADAMS

2012 ◽  
Vol 152-154 ◽  
pp. 1077-1081 ◽  
Author(s):  
Zhao Qi He ◽  
Yu Chao Song ◽  
Hong Liang Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Excitation Frequency ◽  
Vibration Isolator ◽  
Vibration System ◽  
Linear Vibration ◽  
External Excitation ◽  
Mass Model ◽  
Adams Software ◽  
Isolation Systems

A nonlinear spring-mass model is established to study the dynamic characteristics of nonlinear vibration isolator. By use of ADAMS software, the influence of stiffness, foundation displacement excitation and frequency of external excitation on the nonlinear vibration isolation systems are analyzed. Results indicate that the linear vibration system needs 4s to achieve stability, but the nonlinear vibration system only needs 0.1s. The response value increases with the increase of excitation frequency, the response pick value increases by 61.58% and 102.35% and each corresponding stable value increases by 159.35% and 309.87%.

scholarly journals A New Approach to Achieve Variable Negative Stiffness by Using an Electromagnetic Asymmetric Tooth Structure

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chao Han ◽  
Xueguang Liu ◽  
Muyun Wu ◽  
Weilong Liang
Keyword(s):  
Vibration Isolation ◽  
Excitation Frequency ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Excellent Performance ◽  
New Approach ◽  
Tooth Structure ◽  
Vibration Isolators ◽  
Electromagnetic Vibration

Traditional passive nonlinear isolators have been paid much attention in recent literatures due to their excellent performance compared to linear vibration isolators. However, they are incapable of dealing with varying conditions such as changing excitation frequency due to the nonadjustable negative stiffness. To solve this drawback, a new approach to achieve variable negative stiffness is proposed in this paper. The negative stiffness is realized by an electromagnetic asymmetric magnetic tooth structure and can be changed by adjusting the magnitude of the input direct current. Analytical model of the electromagnetic force is built and simulations of magnetic field are conducted to validate the negative stiffness. Then the EATS is applied to vibration isolation and an electromagnetic vibration isolator is designed. Finally, a series of tests are conducted to measure the negative stiffness experimentally and confirm the effect of the EATS in vibration isolation.

Vibration control of an unbalanced system using a quasi-zero stiffness vibration isolator with fluidic actuators and composite material: An experimental study

2022 ◽  
pp. 107754632110514
Author(s):  
Sivakumar Solaiachari ◽  
Jayakumar Lakshmipathy
Keyword(s):  
Composite Material ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Basalt Fiber ◽  
Experimental Investigations ◽  
Vibration Isolator ◽  
Coil Spring ◽  
Linear Type ◽  
Fluidic Actuators ◽  
Isolation Performance

In this study, a new type of vibration isolator based on fluidic actuators and a composite slab was tested experimentally with an unbalanced disturbance. Quasi-zero stiffness vibration isolation techniques are advanced and provide effective isolation performance for non-nominal loads. The isolation performance of the proposed isolator was compared to that of a nonlinear vibration isolator equipped with fluidic actuators and a mechanical coil spring (NLVIFA). The NLVIFA system is better suited to non-nominal loads; however, the mechanical spring axial deflection leads to limited amplitude reduction in the system. To address this issue, a cross buckled slab was developed to replace a mechanical coil spring for absorbing vertical deflection by transverse bending, which is made of a specially developed composite material of Basalt fiber reinforced with epoxy resin and enhanced with graphene nano pellets. This current study was concerned with the theoretical analysis and experimental investigations of the proposed nonlinear vibration isolator with fluidic actuators and composite material (NLVIFA-CM), which performs under quasi-zero stiffness characteristics. Because of its reduced axial deflection, the theoretical and experimental results show that the NLVIFA-CM system outperforms the NLVIFA system and other linear type vibration isolators in terms of isolation performance. Furthermore, the proposed vibration isolator makes a significant contribution to low-frequency vibration.

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.

On the Effects of Mistuning a Force-Excited System Containing a Quasi-Zero-Stiffness Vibration Isolator

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Ali Abolfathi ◽  
M. J. Brennan ◽  
T. P. Waters ◽  
B. Tang
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Vibration Isolators ◽  
Zero Dynamic ◽  
Low Frequency Vibration ◽  
Excited System ◽  
Better Than

Nonlinear isolators with high-static-low-dynamic-stiffness have received considerable attention in the recent literature due to their performance benefits compared to linear vibration isolators. A quasi-zero-stiffness (QZS) isolator is a particular case of this type of isolator, which has a zero dynamic stiffness at the static equilibrium position. These types of isolators can be used to achieve very low frequency vibration isolation, but a drawback is that they have purely hardening stiffness behavior. If something occurs to destroy the symmetry of the system, for example, by an additional static load being applied to the isolator during operation, or by the incorrect mass being suspended on the isolator, then the isolator behavior will change dramatically. The question is whether this will be detrimental to the performance of the isolator and this is addressed in this paper. The analysis in this paper shows that although the asymmetry will degrade the performance of the isolator compared to the perfectly tuned case, it will still perform better than the corresponding linear isolator provided that the amplitude of excitation is not too large.

scholarly journals STRUCTURAL OPTIMIZATION OF LINEAR VIBRATION ISOLATION SYSTEMS

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
ZH. B. BAKIROV ◽  
M. ZH. BAKIROV ◽  
G. D. TAZHENOVA ◽  
ZH. S. NUGUZHINOV
Keyword(s):  
Structural Optimization ◽  
Vibration Isolation ◽  
Linear Vibration ◽  
Isolation Systems

Application of Compliant Mechanisms to Active Vibration Isolation Systems

2004 ◽  
Author(s):  
Tanakorn Tantanawat ◽  
Zhe Li ◽  
Sridhar Kota
Keyword(s):  
Vibration Isolation ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Vibration Isolator ◽  
External Energy ◽  
Low Frequencies ◽  
Output Amplitude ◽  
Active Vibration ◽  
Isolation Systems ◽  
Active Vibration Isolation

Compliant mechanisms have been designed for various types of applications to transmit desired forces and motions. In this paper, we explore an application of compliant mechanisms for active vibration isolation systems. For this type of application, an actuator and a compliant mechanism are used to cancel undesired disturbance, resulting in attenuated output amplitude. An actuator provides external energy to the system while a compliant mechanism functions as a transmission controlling the amount of displacement transmitted from the actuator to the payload to be isolated. This paper illustrates, based on preliminary results of finite element analyses (FEA), that a compliant mechanism equipped with an actuator can be used as an active vibration isolator to effectively cancel a known sinusoidal displacement disturbance at low frequencies by using a feedforward disturbance compensation control. The nonlinear FEA shows that a sinusoidal displacement disturbance of 6.0 mm amplitude is reduced by 95% at 3.9 Hz and 91% at 35.1 Hz with a sinusoidal displacement controlled input of 0.73 mm amplitude.

Nonlinear Vibration Characteristics of Fatigue Damaged Reinforced Concrete Structures

2005 ◽  
Vol 297-300 ◽  
pp. 2592-2597
Author(s):  
Jin Ho Kim
Keyword(s):  
Reinforced Concrete ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Concrete Structures ◽  
Analytical Models ◽  
Fatigue Properties ◽  
Reinforced Concrete Structures ◽  
Isolation System ◽  
Discrete Crack ◽  
Isolation Systems

In this paper, nonlinear vibration techniques were applied to investigate stages of progressive damage in three vibration isolation systems induced by dynamic loadings. Analytical models for reinforced concrete structures of three isolation systems were developed based on FEM with discrete crack concept. Vibration response spectra and the spectra of forces transmitted through the isolators were computed with respect to stationary dynamic loads. In addition, fatigue properties of concrete structures were examined for given materials’ properties and given geometries. The results indicated that the proposed isolation system 3 can improve fatigue resistance by extending fatigue life and changing the failure mode from shear to flexure.

Identification of a Nonlinear Vibration System Using Simulated Annealing, Genetic Algorithm and Programming

1999 ◽  
Author(s):  
Lubomir Sláma ◽  
Mojmir Balátě ◽  
Jiří Krejsa ◽  
Jan Slavík
Keyword(s):  
Genetic Algorithm ◽  
Simulated Annealing ◽  
Genetic Programming ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Vibration System ◽  
Isolation System ◽  
Simulated Annealing Genetic Algorithm ◽  
Damping Characteristics ◽  
Nonlinear Vibration System

Abstract Application of genetic algorithm and genetic programming to identification of a nonlinear vibration system is presented. Both the theoretical groundwork and experimental results are included. The genetic algorithm is used for identification of parameters of nonlinear stiffness and friction damping characteristics of a single-degree-of-freedom model of a vibration isolation system. The genetic programming is used for identification of a functional form and parameters of a load-deflection characteristic of a rubber isolator. Obtained results from computational experiments are presented and discussed. Results of GA are compared to results obtained by using a simulated annealing method.

Experimental Study of the Variable Stiffness Vibration Isolator

2011 ◽  
Vol 328-330 ◽  
pp. 2129-2133 ◽  
Author(s):  
Zhi Jun Shuai ◽  
Tie Jun Yang ◽  
Zhuo Liang Zhou ◽  
Zhi Gang Liu
Keyword(s):  
Natural Frequency ◽  
Vibration Isolation ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Variable Stiffness ◽  
Resonance Problem ◽  
Vibration Isolator ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Passive Vibration Isolation

The traditional passive vibration isolation system can reduce the vibration transmission greatly while the excitation frequency is times higher than its natural frequency. As the external excitation approach its natural frequency, vibration isolator system is invalid. In this paper, a new variable stiffness vibration isolator was designed to solve the low-frequency resonance problem of the traditional isolator by combining toothed electromagnetic spring with passive isolator. Theoretical analysis and experimental results illustrate that this isolator met the design requirements and obtained the no resonance operating characteristic at the low frequency.

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