Analysis of Nonlinear Cyclically Symmetric Isolation Sistem of a Cargo in a Container under Plane Harmonic Vibrations

2021 ◽  
pp. 32-50
Author(s):  
A.E. Belkin ◽  
I.Z. Dashtiev ◽  
E.A. Nikitin
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Excitation Amplitude ◽  
High Energy ◽  
Symmetric System ◽  
Model Framework ◽  
Isolation System ◽  
Kinematic Excitation ◽  
Shock Absorbers ◽  
High Energy Absorption

The problem of calculating the system of a cylindrical shaped load transverse damping installed in a coaxial container is considered. This system has several annular belts of insulation with a cyclically symmetric arrangement of shock absorbers along the circumferential direction. A simple dynamic model of one insulation belt formed by polyurethane tunnel-type shock absorbers is investigated. Such shock absorbers have a high energy absorption coefficient and can operate at very high drafts comparable to their height, which is important when the space between the cargo and the container wall is limited. Within the proposed model framework, a harmonic nonlinear analysis of cargo plane oscillations under kinematic excitation coming from the container is considered. A method for reducing a nonlinear cyclically symmetric system with discrete elastic elements, which allows limiting the analysis to the calculation of a vibration isolation system with one degree of freedom, is proposed. Using the harmonic linearization procedure, the amplitude-frequency characteristics of oscillations and plots of vibration isolation coefficients of cargo at different values of excitation amplitude have been obtained. The results are verified by comparing the analytical solution with the results of numerical integration for a non-reduced nonlinear system with two degrees of freedom. The obtained solution allows choosing the vibration isolation belt parameters, in particular the number of shock absorbers and their stiffness, depending on the conditions of kinematic excitation and permissible overload

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.

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.

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.

Numerical Study on the Application of Chaos in Line Spectrum Reduction

2009 ◽  
Author(s):  
Jingjun Lou ◽  
Shijian Zhu
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Numerical Study ◽  
Excitation Amplitude ◽  
Point Of View ◽  
Line Spectrum ◽  
Chaotic State ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Two Degree Of Freedom

The application of chaos method in line spectrum reduction is numerically studied. The nonlinear dynamics and the power flow transmissibility of a two-degree-of-freedom vibration isolation system with nonlinear spring are analyzed. The dynamic behavior distribution chart of the system is obtained. Cascades of bifurcation of the system with different excitation amplitude are also gained. The isolation effectiveness is analyzed from the point of view of energy. The numerical results show that the reduction of the line spectrum in chaotic state is much greater than that in non-chaotic state.

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.

scholarly journals Modeling and Control of a Six Degrees of Freedom Maglev Vibration Isolation System

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3608 ◽  
Author(s):  
Qianqian Wu ◽  
Ning Cui ◽  
Sifang Zhao ◽  
Hongbo Zhang ◽  
Bilong Liu
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Nonlinear Dynamic Model ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Modeling And Control ◽  
And Control ◽  
Isolation Performance

The environment in space provides favorable conditions for space missions. However, low frequency vibration poses a great challenge to high sensitivity equipment, resulting in performance degradation of sensitive systems. Due to the ever-increasing requirements to protect sensitive payloads, there is a pressing need for micro-vibration suppression. This paper deals with the modeling and control of a maglev vibration isolation system. A high-precision nonlinear dynamic model with six degrees of freedom was derived, which contains the mathematical model of Lorentz actuators and umbilical cables. Regarding the system performance, a double closed-loop control strategy was proposed, and a sliding mode control algorithm was adopted to improve the vibration isolation performance. A simulation program of the system was developed in a MATLAB environment. A vibration isolation performance in the frequency range of 0.01–100 Hz and a tracking performance below 0.01 Hz were obtained. In order to verify the nonlinear dynamic model and the isolation performance, a principle prototype of the maglev isolation system equipped with accelerometers and position sensors was developed for the experiments. By comparing the simulation results and the experiment results, the nonlinear dynamic model of the maglev vibration isolation system was verified and the control strategy of the system was proved to be highly effective.

Development of Six Degrees of Freedom Vibration Isolation System for Microgravity Environment

1995 ◽  
Author(s):  
Toshiyuki Suzuki ◽  
Koji Tanida ◽  
Akira Tanji ◽  
Koichi Okubo
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Parabolic Flight ◽  
Microgravity Environment ◽  
External Disturbances ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Six Degrees Of Freedom ◽  
Active Vibration ◽  
Good Agreement

Abstract An active vibration isolation system, under development for use in microgravity environment, provides electromagnetic suspension by means of voice coils arranged in pairs to control the translational and rotational movements of the payload, three pairs of which cover the three axes to ensure control of payload movement in all six degrees of freedom. A series of tests performed on this system in microgravity environment created by parabolic flight proved that external disturbances in frequencies above 0.1 Hz were effectively reduced by applying the system. Also, good agreement was obtained between the measured performance and results of numerical simulation.

An Active Microvibration Isolation System for Hi-tech Manufacturing Facilities

2000 ◽  
Vol 123 (2) ◽  
pp. 269-275 ◽  
Author(s):  
H. Yoshioka ◽  
Y. Takahashi ◽  
K. Katayama ◽  
T. Imazawa ◽  
N. Murai
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Isolation ◽  
Tuned Mass Damper ◽  
Impact Excitation ◽  
Frequency Range ◽  
Isolation System ◽  
Linear Motors ◽  
Assignment Method ◽  
Mass Damper ◽  
Bending Modes

This paper presents an active microvibration isolation system using voice-coil linear motors, and pneumatic and piezoelectric actuators. This system is designed to reduce microvibration of the six degrees-of-freedom associated with the rigid body modes of the vibration isolation table by feeding back the pseudo absolute displacement and velocity of the table. To improve vibration isolation performance, a feed-forward control link is added to the sway components in each dimension. This system can also control bending modes of the table in the frequency range up to 200 Hz by employing a proposed Virtual Tuned-Mass Damper control strategy, which is a type of the pole assignment method. In this approach, the pole locations are chosen by a genetic algorithm. For ambient microvibration of the floor around 0.5 cm/s2 and for small earthquakes of around 8 cm/s2 a reduction by a factor of 100 was achieved in the acceleration of the vibration isolation table. Moreover, the vibration of the isolation table was decreased over the entire frequency range. This system also showed good vibration control performance when an impact excitation was applied directly to the table; vibration was damped out within about 0.1 sec. Additionally, the resonance amplitudes around the bending modes of the table were reduced from 1/5 to 1/15 by the Virtual Tuned-Mass Damper method.

Vibration Isolation Analysis of Vibrating Screen with Two-Mass and High Energy

2013 ◽  
Vol 427-429 ◽  
pp. 112-115
Author(s):  
Xiao Lan Yang ◽  
Ji Feng Liu ◽  
Bing Zhi Kong ◽  
Xiao Lin Jia ◽  
Xiao Feng Yang ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
High Energy ◽  
System Stability ◽  
Good Effect ◽  
Lower Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Intensity ◽  
Vibrating Screen ◽  
The One

To break through the drawbacks of the one-mass vibrating screen like plugging screen, high noise and etc., a new vibration screen with two-mass and high energy which could generate transient high vibration intensity was analyzed. To meet the requirements of energy-saving and system stability, a spring with nonlinear and hard features was used in the main vibration system. In this case, the springs stiffness could change along with the vibration intensity. The stiffness of the vibration isolation spring could be determined by analyzing the vibration isolation coefficient, and then the hollow cylindrical rubber spring with internal damping was adopted in the vibration isolation system. On the one hand, this vibration isolation spring could effectively absorb transient high vibration intensity which passed from main vibrating spring to the lower mass. On the other hand, it could achieve good effect of vibration isolation between the lower mass and the foundation. Base on field testing, the vibration intensity was increased by 28%, meanwhile, the noise was reduced by 4% and the impact vibration to foundation was reduced by 24% , which successfully solved the plugging screen problem and also verified the validity of the vibration isolation system.

Sign in / Sign up

Export Citation Format

Share Document