Force transmissibility of floating raft systems with quasi-zero-stiffness isolators

2017 ◽  
Vol 24 (16) ◽  
pp. 3608-3616 ◽  
Author(s):  
Li Yingli ◽  
Xu Daolin
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Low Frequency ◽  
Frequency Region ◽  
Mass Ratio ◽  
Isolation System ◽  
Floating Raft ◽  
Highly Nonlinear ◽  
Vibration Attenuation ◽  
Force Transmissibility

In view of the excellent performance of a single quasi-zero-stiffness (QZS) device in vibration attenuation, this paper presents a study on a vibration isolation floating raft system constructed with a double-layer QZS mechanism. A QZS device is a typical nonlinear isolator, hence the floating raft system is a coupled highly nonlinear isolation system. To understand the behaviors and its performance in vibration attenuation, an analytical approach is developed to describe the characteristics including the mathematical relationship between amplitude–frequency, force transmissibility, and the effects of the mass ratio and damping ratios on attenuation performance. The outcomes show that the two-degree-of-freedom QZS–QZS system is superior for vibration isolation when compared to the traditional linear system and the two other types of QZS systems. The effective vibration isolation frequency region of the QZS–QZS system is expanded to the low-frequency region by 72%. The QZS system is sensitive to the damping ratio, which decreases the resonance peak significantly. The mass ratio is a crucial design parameter in low-frequency vibration isolation design.

scholarly journals The active dynamic vibration damper in non-stationary operation of a vibroactive unit

2021 ◽  
pp. 13-17
Author(s):  
D. V. Sitnikov ◽  
◽  
A. A. Burian ◽  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Resonance Region ◽  
Frequency Region ◽  
Vibration Damper ◽  
Passive System ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Dynamic Vibration ◽  
Impulse Characteristics

The paper considers a vibration isolation system, in which a force is applied to the moving mass of the active dynamic vibration damper by an actuator in proportion to the measured value of the base response. The amplitude-frequency and impulse characteristics are plotted depending on the parameters of the system, assuming the actuator without distortion generates the force proportional to the base response. It is shown that the considered vibration isolation system is quite effective in the low-frequency region, including in the resonance region of the passive system, both in stationary and nonstationary modes of vibroactive forces

Design of Vibration Isolation Device for Ship Power Equipment and Investigation on its Dynamic Properties

2014 ◽  
Vol 496-500 ◽  
pp. 1129-1133
Author(s):  
Yuan Yuan Fang ◽  
Guo Hong Zhang ◽  
Ya Fan Li ◽  
Peng Zhe Qi
Keyword(s):  
Vibration Isolation ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Power Equipment ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Radiated Noise ◽  
Spring Element ◽  
Floating Raft ◽  
Isolation Device

Mechanical noise caused by power equipment vibration is the main source of underwater radiated noise of the ship, and vibration isolation and noise reduction of ship equipment has been widely concerned. Therefore,a vibration isolation system designed for four sets of auxiliary engine of ship cabin was investigated in the paper, aimed to further reveal the influence of various parameters including floating raft shell thickness, excitation source, and different ship hull and installation platform thickness on the vibration level difference of system. The results obtained from numerical analysis using MSC software and experiment indicate that one-dimensional spring element simplified can properly simulate the actual rubber vibration isolator on low frequency bands, and increasing thickness of flat, hull and platform can improve the effect of vibration isolation obviously.

Force transmissibility of a two-stage vibration isolation system with quasi-zero stiffness

2016 ◽  
Vol 87 (1) ◽  
pp. 633-646 ◽  
Author(s):  
Xinlong Wang ◽  
Jiaxi Zhou ◽  
Daolin Xu ◽  
Huajiang Ouyang ◽  
Yong Duan
Keyword(s):  
Vibration Isolation ◽  
Two Stage ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Force Transmissibility

Design of an effective vibration isolation system for measurements sensitive to low-frequency vibrations

2012 ◽  
Vol 30 (6) ◽  
pp. 063201 ◽  
Author(s):  
Katsuya Iwaya ◽  
Ryota Shimizu ◽  
Akira Teramura ◽  
Seiji Sasaki ◽  
Toru Itagaki ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Low Frequency ◽  
Isolation System ◽  
Vibration Isolation System

Research on Vibration Isolation Parameters of Double-Deck Isolation System of Heat Water Pump

2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Mass Effect ◽  
Transmitted Power ◽  
Intermediate Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Upper Deck ◽  
Vibration Power Flow

Isolation system of the heat water pumps can be simplified as a double sources exciting and double output double-deck vibration isolation system model, expressions of transmitted power flow and vibration speed to the basement are deduced based on the double sources exciting and double output double-deck vibration isolation system electric-force(E-F) analog picture, the curves of power flow and vibration speed transmitted to basement how the upper deck vibration isolation and intermediate mass effect are drawn by using mat lab program. The results show that the adjusting the upper deck vibration isolation stiffness parameters has little effect on the amplitude of vibration power flow, increasing intermediate mass can move first peak to the low frequency, increasing intermediate mass can obviously reduce t transmitted power flow and transmitted vibration speed amplitude to the basement.

On vibration isolation of sandwich plate with periodic hollow tube core

2017 ◽  
Vol 21 (3) ◽  
pp. 1119-1132 ◽  
Author(s):  
Gui-Lan Yu ◽  
Hong-Wei Miao
Keyword(s):  
Vibration Isolation ◽  
Sandwich Plate ◽  
Experimental Studies ◽  
Low Frequency ◽  
Dispersion Relations ◽  
Frequency Responses ◽  
Vibration Attenuation ◽  
Potential Applications ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolation performance of a PC sandwich plate with periodic hollow tube core is investigated experimentally and numerically. The experiment results reveal that there exist vibration attenuation zones in acceleration frequency responses which can be improved by increasing the number of periods or tuning some structure parameters. The presence of soft fillers shifts the attenuation zone to lower frequencies and enhances the capability of vibration isolation to some extent. Dispersion relations and acceleration frequency responses are calculated by finite element method using COMSOL MULTIPHYSICS. The attenuation zones obtained by experiments fit well with that by simulations, and both are consistent with the band gap in dispersion relations. The numerical and experimental studies in the present paper show that this PC sandwich plate exhibits a good performance on vibration isolation in low frequency ranges, which will provide some useful references for relevant research and potential applications in vibration propagation manipulations.

scholarly journals Analysis and design of the power law damping based on the nonlinear vessel isolation system

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881719 ◽  
Author(s):  
You Wang ◽  
Xinghua Zhu ◽  
Rong Zheng ◽  
Zhe Tang ◽  
Bingbing Chen
Keyword(s):  
Resonant Frequency ◽  
Working Conditions ◽  
Power Law ◽  
Nonlinear Damping ◽  
Frequency Region ◽  
Isolation System ◽  
Analysis And Design ◽  
Force Transmissibility ◽  
Isolation Systems ◽  
Isolation Performance

In this study, the applications of the cubic power law damping in vessel isolation systems are investigated. The isolation performance is assessed using the force transmissibility of the vessel isolation system, which is simplified as a multiple-degree-of-freedom system with two parallel freedoms. The force transmissibilities of different working conditions faced in practice are discussed by applying the cubic power law damping on different positions of the vessel isolation system. Numerical results indicate that by adding the cubic power law damping to an appropriate position, the isolation system can not only suppress the force transmissibility over the resonant frequency region but also keep the force transmissibility unaffected at the nonresonant frequency region. Moreover, the design of the nonlinear vessel isolation system is discussed by finding the optimal nonlinear damping of the isolation system.

The Vibration Isolation Effect Research of the Floating Raft Isolation System Based on the Adjustable Flexibility of Foundation

2013 ◽  
Vol 819 ◽  
pp. 115-119 ◽  
Author(s):  
Hui Wang ◽  
Ze Yu Weng ◽  
Gan Xiang ◽  
Bo Lu ◽  
Hong Gang Ding ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Test System ◽  
Isolation Effect ◽  
Isolation System ◽  
Elastic Beams ◽  
Floating Raft ◽  
Marine Engineering ◽  
Flexible Foundation ◽  
The Relationship ◽  
Theoretical Results

The floating raft isolation system is widely used in the field of marine engineering for its vibration isolation effect. Along with the application of light thinning structure of the ship, the flexibility of foundation of floating raft isolation system makes the vibration isolation effect vary widely between the practical floating raft isolation system and its theoretical results. In order to research the vibration isolation effect of the floating raft isolation system on different flexibility of foundation, the floating raft isolation system with flexible foundation is designed in this paper, and the adjustable flexibility of foundation is achieved by using elastic beams. With simulation and analysis of test system in ADAMS, the results of the relationship between flexibility and vibration isolation effect are obtained.

scholarly journals Design, Experiment, and Improvement of a Quasi-Zero-Stiffness Vibration Isolation System

2020 ◽  
Vol 10 (7) ◽  
pp. 2273 ◽  
Author(s):  
Shuai Wang ◽  
Wenpen Xin ◽  
Yinghao Ning ◽  
Bing Li ◽  
Ying Hu
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Linear Spring ◽  
Isolation Effects ◽  
Magnetic Rings ◽  
The Relationship ◽  
Force Displacement

This paper proposes a new kind of quasi-zero-stiffness (QZS) isolation system that has the property of low-dynamic but high-static stiffness. The negative stiffness was produced using two magnetic rings, the magnetization of which is axial. First, the force–displacement characteristic of the two coupled magnetic rings was developed and the relationship between the parameters of the magnetic rings and the stiffness of the system was investigated. Then, the dynamic response of the QZS was analyzed. The force transmissibility of the system was calculated and the effects of the damping ratio and excitation amplitude on the isolation performance were investigated. The prototype of the QZS system was developed to verify the isolation effects of the system based on a comparison with a linear vibration isolation platform. Lastly, the improvement of the QZS system was conducted based on changing the heights of the ring magnets and designing a proper non-linear spring. The analysis shows the QZS system after improvement shows better isolation effects than that of the non-improved system.

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