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 and Research of Semiactive Quasi-Zero Stiffness Vibration Isolation System for Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Shaohua Li ◽  
Guizhen Feng ◽  
Quan Zhao
Keyword(s):  
Embedded System ◽  
Vibration Isolation ◽  
Test System ◽  
Isolation Effect ◽  
Vertical Acceleration ◽  
Vibration Isolator ◽  
Isolation System ◽  
Labview Software ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vehicle-mounted equipment is easy to be disturbed by external vibration excitations during transportation, which is harmful to the measurement accuracy and performance of the equipment. Aiming at the vibration isolation of the vehicle-mounted equipment, a semiactively controlled quasi-zero stiffness (QZS) vibration isolator with positive and negative stiffness is proposed. The vertical spring is paralleled with a magnetorheological (MR) damper, and the semiactive on-off control scheme is adopted to control the vibration. The analytical expression of the isolator’s displacement transmissibility is derived via the averaging method. Then, the vibration isolation performance under different road excitations and different driving speeds is simulated and compared with the uncontrolled passive QZS vibration isolator. In addition, the mechanical structure of the semiactive QZS isolator is designed and manufactured, and the test system is built by LabVIEW software and PXI embedded system. The isolation effect of the semiactive QZS isolator is verified through test data. It is found that the proposed semiactive QZS isolator shows excellent vibration isolation performance under various road excitations, while the passive QZS isolator is effective only under harmonic excitations. The vertical acceleration of vehicle-mounted device can be decreased over 70% after isolation, and the vibration isolation effect is remarkable. The design idea and research results of the semiactive QZS isolator may provide theoretical guidance and engineering reference for vibration isolation.

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.

Study on Floating Raft Vibration Isolation System for Pumping Unit

2011 ◽  
Vol 383-390 ◽  
pp. 130-135 ◽  
Author(s):  
Fu Mao Wang ◽  
Chang Guo Wang ◽  
Lan Lan Guo ◽  
Bang Chun Wen ◽  
Yong Li
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
Vibration Isolation ◽  
Steel Structure ◽  
Elastic Cylinder ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Floating Raft ◽  
Pumping Units ◽  
Important Basis

In this paper, based on the theory of double layered vibration isolation, the finite element dynamic model of floating raft vibration isolation system has been established for the project of vibration and noise control in a heat exchange station. The dynamic model of single pump is simplified an elastic cylinder based on the principle of equivalent parameters, and the elastic raft frame is used of steel structure. The dynamic characteristics of the system is analyzed by used of ANSYS with SOLID45 unit and COMBIN14 spring-damper unit, which provide an important basis for the engineering design of floating raft isolation system with pumping units.

Theory and Method of Dynamic Modeling for Multilayer Vibration Isolation System

2000 ◽  
Author(s):  
Liao Dao-Xun ◽  
Lu Yong-Zhong ◽  
Huang Xiao-Cheng
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Rigid Bodies ◽  
Design Calculation ◽  
Isolation System ◽  
Dry Land ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Floating Raft

Abstract The multilayer vibration isolation system has been widely applied to isolate vibration in dynamic devices of ships, high-speed vehicles forging hammer and precise instruments. The paper is based on the coordinate transformation of space general motion for mass blocks (rigid bodies) and Lagrangian equation of multilayer vibration isolation system. It gives a strict mathematical derivation on the differential equation of the motion for the system with six degrees of freedom of relative motion between mass blocks (including base). The equations are different from the same kind of equations in the reference literatures. It can be used in the floating raft of ships in order to isolates vibration and decrease noise, also used in design calculation of the multilayer vibration isolation for dynamic machines and precise instruments on the dry land.

The Influence of Piping Arrangement on the Response of Vibration Isolation System Under Underwater Explosion Loading

2019 ◽  
Author(s):  
Chen Pan ◽  
Wei Qiang ◽  
Liu Zhizhong ◽  
Wang Guan
Keyword(s):  
Shock Loading ◽  
Vibration Isolation ◽  
Underwater Explosion ◽  
Mechanical Equipment ◽  
Piping System ◽  
Flexible Pipe ◽  
Isolation System ◽  
Floating Raft ◽  
Shock Resistance ◽  
Actual Response

Abstract The response of ship equipment under non-contact underwater explosion shock loading was one of the main loadings of equipment. In order to cut down mechanical noise caused by mechanical equipment, vibration isolation measures, such as floating raft, vibration isolation, were widely used on noise mechanical equipments in acoustical stealth of ship, vibration isolation can reduce the vibration transfer to install base effectively, while the anti-shock resistance of vibration isolation and the equipment was important synchronously, as for the response of the equipment on vibration isolation, especially the actual response of the vibration isolation with piping system under shock loading. In this paper, the research on the response of vibration isolation, equipment, flexible piping and piping under underwater explosion shock loading were considered together, and the response of vibration isolation under shock load was analyzed with different piping arrangement. Found that the piping system has a significant impact on the response of the equipment under horizontal impact, but almost all equipments were assessed in experiment without considering the piping system. With the precondition of the effect of vibration isolation, a more rigid flexible pipe can be taken was benefit to the anti-shock resistance of vibration isolation.

scholarly journals Vibration Isolation of Existing Buildings in Microvibration Traffic Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Qian Xia ◽  
Wen-jun Qu ◽  
Yi-qing Li ◽  
Jin Zhao
Keyword(s):  
Vibration Isolation ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Isolation Effect ◽  
Slab Thickness ◽  
Filling Material ◽  
Construction Technology ◽  
Existing Buildings ◽  
Isolation System ◽  
The Impact

In order to explore the impact of traffic environmental microvibration on buildings, this paper studies indoor vibration isolation, a method applicable to existing buildings. The vibration isolation scheme is designed based on the residential buildings adjacent to metro lines in Shanghai. By using the dynamic theory, the effective range of vibration isolation stiffness is analyzed. The effectiveness of the indoor vibration isolation method is verified through theoretical calculations and comparison of field measurements before and after isolation. A detailed numerical model is established to analyze the indoor isolation and the effect after parameter optimization from the slab thickness, filling material, and isolator stiffness. The results show that the isolation effect is proportional to the thickness of the total slab thickness of the isolation system and inversely proportional to the stiffness of the isolator. And when concrete is used as the filling material, the isolation effect is best. The isolation effect of the midspan position is better than that of the wall-floor junction. The vibration isolation effect is more obvious after the parameters are optimized. With its convenient construction technology, short cycle, and low cost, this method is worth promoting.

Modeling Research for Active Control of Coupled Vibration between Multiple CNC Milling Machines and Flexible Foundation

2011 ◽  
Vol 105-107 ◽  
pp. 675-679 ◽  
Author(s):  
Fu Dong Ma ◽  
Yao Gang Li ◽  
Qian Lin Peng
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Lagrange Equation ◽  
Real Life ◽  
Traditional Theory ◽  
Cnc Milling ◽  
Isolation System ◽  
Milling Machines ◽  
Flexible Foundation ◽  
Multiple Machines

In real life many agencies are using the flexible foundation as a base of support, such as ship hull or deck, the chassis of car, and machine tools work on stairs. With the traditional theory, the mathematical model between machine and based simplified as single-degree-of-freedom, assuming foundation is a rigid, and many investigate for a single machine, ignoring the dynamic coupling of base and the coupling characteristics between vibrators. This paper build a dynamics model with flexible basis and multiple machines, it’s multi-degrees-of-freedom model. The foundation is flexibled. On this basis builiding a model about multiple machines, flexible foundation and vibration isolation system. This paper resolve to the problem of the machine work on stair, research the system include vibrator, actuators, and flexible foundation. Using Lagrange equation deduce dynamics equation. Express every factor in eqution,deduced the state and space expression.Take prepare for optimal and system simulation.

Dynamic Analysis of Multi-Supported Nonlinear Vibration Isolation System Mounted on Flexible Foundation

2013 ◽  
Vol 419 ◽  
pp. 223-227 ◽  
Author(s):  
Rui Huo ◽  
Hui Yu ◽  
Yan Feng Guan
Keyword(s):  
Numerical Solution ◽  
Nonlinear Vibration ◽  
Power Flow ◽  
Vibration Isolation ◽  
Engineering Application ◽  
System Dynamic ◽  
Dynamic Equations ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Flexible Foundation

In view of its prototype in engineering application, a theoretical model of multi-supported nonlinear vibration isolation system installed on flexible foundation is studied, including derivation of system dynamic equations and analysis of system dynamic characteristics. For effectiveness evaluation of nonlinear vibration isolation systems, a generalized time-averaged power is proposed as an extension of classical theory of vibratory power flow, and a numerical solution method of time-averaged power is probed accompanying with the numerical solution of nonlinear dynamic equations. In a further concrete calculation example, an air spring vibration isolation system of a small UAV engine is numerically simulated based on Runge-Kutta method, and dynamic behavior and power flow transmission characteristics influenced by system parameters are investigated.

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.

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