Dynamic Analysis of Nonlinear Vibration Isolation System Based on Flexible Foundation

2014 ◽  
Vol 1030-1032 ◽  
pp. 766-769
Author(s):  
Shu Ying Li ◽  
Rui Huo ◽  
Xing Ke Cui ◽  
Cui Ping Liu ◽  
Dao Kun Zhang

In this paper,a general dynamic model of the isolation coupled system which is composed of isolation object,nonlinear vibration isolation support,and flexible foundation is established,calculated method of applying vibration power flow to analyze isolation effectiveness is studied.Further more,as an calculation example,a air spring vibration isolation system of HS-700 engines is numerically simulated.Designs several low-frequency nonlinear vibration isolators and analyzes its vibration isolation effect.It discusses the effect of the vibration isolator parameters on the transmitted power flow of the system.The results provide a theoretical basis for the optimized design of nonlinear vibration isolation system.

2013 ◽  
Vol 419 ◽  
pp. 223-227 ◽  
Author(s):  
Rui Huo ◽  
Hui Yu ◽  
Yan Feng Guan

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.


2013 ◽  
Vol 694-697 ◽  
pp. 316-320
Author(s):  
Xiang Jun Kong ◽  
Er Ming Song ◽  
Chang Zheng Chen

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.


Author(s):  
Kongjie Song ◽  
Lingling Sun ◽  
Yuguo Sun ◽  
Bing Zhang

This paper is dedicated to the structure dynamic modification in an active isolation system supported by a flexible foundation, in order to improve the effectiveness of the active control strategy. The coupled vibration between machine-sprung and flexible foundation substructure is examined, using the subsystem mobility method. The vibration transmission in this coupled system is presented in terms of power flow. The interaction between structure controlled and the adaptive feed-forward controller is investigated theoretically. The numerical results show that: the location of the active mounts and the first mode frequency of the flexible foundation have evident influence on the effect of active control, especially at low-frequency band.


2011 ◽  
Vol 55-57 ◽  
pp. 872-876
Author(s):  
De Zhen Feng ◽  
Fang Zhou ◽  
Zai Mei Zhang ◽  
Hua Guan Liu

The paper analyzes the dynamic relation of asymmetric multi-supported vibration isolation system with flexible foundation, establishes the comprehensive model of passive control and positive control system by using the effective matrix analysis method, analyzes the transmission mechanism and characteristic of vibrational power flow in the flexible vibration isolation system. In order to meet the need of the practical engineering, the paper analyzes and calculates the effect of the machine mass on the input and the transmission power flow in detail. At last, the paper puts forward the measure to reduce vibration energy transmission.


Author(s):  
Xiang Yu ◽  
Shi-Jian Zhu ◽  
Shu-Yong Liu

Nonlinear vibration isolation system (VIS) plays an important role for improving the capability of hydroacoustic stealth of naval vessels. In engineering, Nonlinear VIS is generally a multi-degree-of-freedom system and its mathematical model is a set of coupled differential equations. Nonlinear normal mode (NNM) is an effective tool for decoupling and analyzing the dynamics of this coupled system. In this paper, taking the flexibility of the base into consideration, the equations of motion of an on-board VIS with quadric and cubic nonlinearities is formulated. The NNMs of this multi-degree-of-freedom nonlinear VIS are constructed by using the invariant manifold approach. The invariant surfaces of the NNMs and the decoupled oscillators are presented.


Author(s):  
Wei-Min Mao ◽  
Shi-Jian Zhu ◽  
Hui-Ming Jiang

This article analyzes the process to design hybrid vibration isolation system on flexible foundation. The dynamic model of a hybrid vibration isolation system on flexible foundation is build and the character of power flow transmission is analyzed by sub-system structure impedance synthesis technique and four poles parameter method. The global sensitivity analysis with the Sobol’ method is used to study the global sensitivity behavior of the hybrid vibration isolation system. The multi-objective optimization design method of hybrid vibration isolation system is studied and the mathematic optimization model has been built. Gene algorithm has been used to solve the global optimization problem, and the numerical simulation is carried out.


2020 ◽  
pp. 107754632093376
Author(s):  
Kai Chai ◽  
Shuang Li ◽  
Jun J Lou ◽  
Xiang Yu ◽  
Yong S Liu ◽  
...  

Line spectra chaotification is a principal method to weaken or eliminate the line spectra feature of submarines. However, this method is difficult to obtain chaos under the variable working conditions and small amplitudes. Furthermore, there are multistable attractors in the nonlinear vibration isolation system simultaneously. So, the quality of chaos highly depends on initial conditions and systematic parameters. In this study, the attractor entrainment control and line spectra chaotification of a nonlinear vibration isolation system on the flexible foundation have been studied by using the open-plus-nonlinear-closed-loop method. First, the dynamic equation of the nonlinear vibration isolation system on the flexible foundation was formulated, and its exhaustive bifurcation characteristics were analyzed. The regulations of global characteristics and coexistent attractors were found out. Second, the entrainments between the different attractors were carried out under the open-plus-nonlinear-closed-loop control, which can ensure the system always works in the lowest line spectra intensity and the best overall vibration isolation performance. Finally, an open-plus-nonlinear-closed-loop coupling method was used to achieve generalized chaotic synchronization between the driving system and the response system, which effectively obtained sustainable chaos even under variable working conditions and small amplitudes. Simulation results validate the feasibility and validity of the open-plus-nonlinear-closed-loop method, which achieves the dual goals of effective vibration isolation in the low frequency range and line spectra chaotification under variable working conditions.


2012 ◽  
Vol 30 (6) ◽  
pp. 063201 ◽  
Author(s):  
Katsuya Iwaya ◽  
Ryota Shimizu ◽  
Akira Teramura ◽  
Seiji Sasaki ◽  
Toru Itagaki ◽  
...  

2012 ◽  
Vol 452-453 ◽  
pp. 659-662
Author(s):  
Wei Wang ◽  
Yi Min Deng

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.


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