scholarly journals Modeling and Vibration Analysis of a 3-UPU Parallel Vibration Isolation Platform with Linear Motors Based on MS-DT-TMM

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wei Chen ◽  
Jiaqi Tong ◽  
Hehe Yang ◽  
Fulong Liu ◽  
Zhen Qin ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Transfer Matrix ◽  
Vibration Analysis ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Vibration Isolator ◽  
Suppression Effect ◽  
Linear Motors ◽  
Vibration Experiment ◽  
Simulation Results

The dynamics and vibration characteristics of a 3-UPU parallel mechanism isolator are investigated by theoretical modeling, numerical simulation, and experimental study. The system consists of two platforms, three linear motors, and the Hook hinges. Firstly, the dynamical mathematical model of this vibration isolator is innovatively established and solved by using the discrete-time transfer matrix method of the multibody system (MS-DT-TMM). According to the modeling principle, the transfer matrix of each component is derived, including the upper and lower platforms, Hooke hinges, and linear motors. Then, the dynamical equation of the overall system is obtained by multiplying all transfer matrices. Secondly, the solution of equation is calculated through the setting of boundary conditions. The numerical simulation is carried out according to the known parameters. The dynamical and vibration analysis of the isolation platform is performed, involving the displacement and force characteristics of the branches. Furthermore, in view of the fact that the Hooke hinges and linear motors are simplified as spatial elastic hinges in modeling. The vibration suppression effect caused by adjusting spring stiffness and damping coefficient is discussed. The simulation results verified the correctness of the MS-DT-TMM method through the comparison with ADAMS simulation results. Finally, the prototype of the vibration isolator is constructed and assembled, and the vibration experiment is conducted. By testing the responses of the isolation device mounted on the vibration table, the natural frequency of the isolator is obtained. The purpose of this experiment is to avoid resonance when it is applied as a vibration isolator in the future. This paper provides a theoretical basis for the later vibration research and control scheme design of the 3-UPU parallel vibration isolation platform.

scholarly journals Numerical and Experimental Study on Suppression Effect of Acoustic Black Hole on Vibration Transmission of Refrigerator Compressor

2021 ◽  
Vol 11 (18) ◽  
pp. 8622
Author(s):  
Xiaofei Du ◽  
Qidi Fu ◽  
Jianrun Zhang ◽  
Chaoyong Zong
Keyword(s):  
Numerical Simulation ◽  
Black Hole ◽  
Vibration Suppression ◽  
Structural Vibration ◽  
Flexural Wave ◽  
Response Analysis ◽  
Flexural Waves ◽  
Suppression Effect ◽  
Support Plate ◽  
The Time Domain

The acoustic black hole (ABH) structures have the potential to achieve structural vibration suppression and noise reduction through the effect of the ABH on the concentration and manipulation of flexural waves. In this paper, a new solution is proposed to embed 2-D ABHs on the support plate to suppress the transmission of compressor vibration to the refrigerator body. The vibration and acoustic measurement experiment of the compressor, the support plate and the refrigerator body, and the coherence analysis of the vibration signals and acoustic signal are carried out to determine the influence of the compressor vibration on the vibration of the refrigerator body and the radiation sound of the back wall. The concentration and manipulation effects of 2-D ABH on flexural waves are verified by numerical simulation of flexural wave propagation in the time domain. FEM models of the original support plate and the damping ABH support plate are established to investigate the comprehensive effect of the 2-D ABHs and the damping layers on the vibration characteristics of the support plate through vibration modal and dynamic response analysis. Numerical simulation results show that the 2-D damping ABHs can suppress the vibrations generated by the compressor at specific frequencies in the middle and high-frequency bands from being transmitted to the refrigerator body through the support plate.

Study on Rubbing Failure Between Fan Vanes and Spacer Ring of a Turbo-Fan Engine

2010 ◽  
Author(s):  
Dayi Zhang ◽  
Meng Chen ◽  
Jie Hong ◽  
Miansheng Dou
Keyword(s):  
Numerical Simulation ◽  
Traveling Wave ◽  
Vibration Analysis ◽  
Element Model ◽  
Vibration Test ◽  
Simulation Techniques ◽  
Wave Resonance ◽  
Stator Vane ◽  
Improvement Measures ◽  
Simulation Results

The objective of the present work is the study of the rubbing failure between fan stator vanes and the spacer ring of a Turbo-Fan Engine. The similar failures appeared 2 times in this small turbo-fan engine. The failure mechanism is analysed, in which kinds of factors that could influence the clearance between the rotor and the stator are taken into account. The failure is analysed by means of both test characterizations and numerical simulation techniques. Firstly, a finite element model of the spline joints is used to calculate the stiffness of the fan-rotor considering the influence of locating surface clearance. Secondly, a traveling wave vibration analysis of the spacer ring is performed, as well as the analysis of the stator vane. Finally, the analysis of the vibration test data is performed. The test characterizations and numerical simulation results indicate that, for Engine-1, the large 2×vibration shows a rotor misalignment, at the same time the traveling wave resonance of the spacer ring occurs, these cause the appearance of the failure. For Engine-2, the failure is caused by the rotor unbalance vibration. Some improvement measures are proposed to avoid this failure.

Vibration Suppression Performance of a Desktop Vibration Isolator Supported by Four Air Spring

2017 ◽  
Author(s):  
Yuichi Baba ◽  
Kento Onishi ◽  
Toshihiko Asami
Keyword(s):  
Support System ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Theoretical Calculations ◽  
Small Diameter ◽  
Measuring Instruments ◽  
Vibration Isolator ◽  
Air Spring ◽  
Damping Force ◽  
Vibration Isolators

Desktop vibration isolators are often used as precision measuring instruments. This article discusses the accuracy of performance prediction methods for vibration isolators elastically supported by four air springs. Each air spring possesses a reservoir tank to ensure the natural frequency of the support system remains low and to provide adequate damping force. For practical use, air springs and reservoir tanks should be installed in separate locations and connected by a small-diameter pipe because desktop isolators must be thin. Our previous studies have shown that there is a secondary resonance point in systems supported by air springs with long pipes and reservoir tanks and that it is not simple to theoretically calculate the amplitude and frequency at this point because this type of air spring support system has nonlinear characteristics. In this study, the change in the vibration isolation performance of a desktop vibration isolator with the length of the pipe connecting the main air tank and the reservoir tank of an air spring-supported system was examined experimentally and approximated using theoretical calculations.

scholarly journals H∞ active control of frequency-varying disturbances in a main engine on the floating raft vibration isolation system

2017 ◽  
Vol 37 (2) ◽  
pp. 199-215 ◽  
Author(s):  
Chunsheng Song ◽  
Yao Xiao ◽  
Chuanchao Yu ◽  
Wei Xu ◽  
Jinguang Zhang
Keyword(s):  
Numerical Simulation ◽  
Vibration Isolation ◽  
Control Method ◽  
Mimo System ◽  
Single Frequency ◽  
Isolation System ◽  
Floating Raft ◽  
Power Machinery ◽  
Simulation Results ◽  
Dominant Frequencies

Reducing the vibration of marine power machinery can improve warships' capabilities of concealment and reconnaissance. Being one of the most effective means to reduce mechanical vibrations, the active vibration control technology can overcome the poor effect in low frequency of traditional passive vibration isolation. As the vibrations arising from operation of marine power machinery are actually the frequency-varying disturbances, the H∞ control method is adopted to suppress frequency-varying disturbances. The H∞ control method can solve the stability problems caused by the uncertainty of the model and reshape the frequency response function of the closed loop system. Two-input two-output continuous transfer function models were identified by using the system identification method and are validated in frequency domain of which all values of best fit exceeds 89%. The method of selecting the weighting functions on the mixed sensitivity problem is studied. Besides, the H∞ controller is designed for a multiple input multiple output (MIMO) system to suppress the single-frequency-varying disturbance. The numerical simulation results show that the magnitudes of the error signals are reduced by more than 50%, and the amplitudes of the dominant frequencies are attenuated by more than 10 dB. Finally, the single excitation source dual-channel control experiments are conducted on the floating raft isolation system. The experiment results reveal that the root mean square values of the error signals under control have fallen by more 74% than that without control, and the amplitudes of the error signals in the dominant frequencies are attenuated above 13 dB. The experiment results and the numerical simulation results are basically in line, indicating a good vibration isolation effect.

Numerical Simulation Method of Track Irregularities Based on Secondary Filtering

2014 ◽  
Vol 1008-1009 ◽  
pp. 1525-1529
Author(s):  
Bao Shan Xiang ◽  
Xing Han ◽  
Xue Wei Wang
Keyword(s):  
Numerical Simulation ◽  
Vibration Analysis ◽  
Simulation Method ◽  
External Excitation ◽  
Coupling Vibration ◽  
Filtering Method ◽  
Numerical Simulation Method ◽  
Simulation Results ◽  
The U.S ◽  
Track Irregularities

Track irregularities are the only external excitation in vehicle-bridge coupling vibration analysis and therefore the numerical simulation method of track irregularities is very important. The U.S. frequency spectrum is usually employed to simulate the track irregularities in China. In this paper, the secondary filtering method is introduced to the simulation of track irregularities and MATLAB programing is employed to simulate an example. Based on the comparison of the simulation results and the objective function, it is indicated that the simulation result is reliable and the method is feasible.

Finite Element Analysis of Chaotic Vibration Isolation System

2011 ◽  
Vol 94-96 ◽  
pp. 2057-2060
Author(s):  
Wei Jun Tao ◽  
Shi Huan ◽  
Xiang Qian Tan ◽  
Guo Ping Jiang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Vibration Isolation ◽  
Simplified Model ◽  
Element Analysis ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Chaotic Vibration ◽  
Model Dynamics ◽  
Simulation Results

A multi-degree-of-freedom (MDOF) vibration isolation system (VIS) model is established with finite element method. And the numerical simulation results of the model under axisymmetric load in a good fit to the simplified model results. The model dynamics behavior under any load also was calculated, and it makes a further analysis for the vibration isolation effect of the model.

scholarly journals Experimental Research and Analysis of Vortex Excited Vibration Suppression of Spiral Stripe Strake

2014 ◽  
Vol 8 (1) ◽  
pp. 941-947
Author(s):  
Zhongguo Yang
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Experimental Research ◽  
Vibration Suppression ◽  
Theoretical Research ◽  
Suppression Effect ◽  
Excited Vibration ◽  
Suppression Mechanism ◽  
Computational Fluid Dynamics Cfd ◽  
Viv Suppression

This paper carries out the experimental research and analysis on the vortex-excited vibration suppression effect of the spiral stripe strake via the laser particle velocimeter (PIV) under vortex speed U=0.6 m/s and attack angle α=300, and discusses the VIV suppression mechanism of the spiral stripe strake by using the numerical simulation of the computational fluid dynamics (CFD) in order to objectively further know inherent mechanism of VIV, further optimize parameters of the spiral stripe strake, and provide references for theoretical research in future.

Avalanche Features in Silicon Schottky-FETs in Accordance with Numerical Simulation Results

2006 ◽  
Vol 65 (16) ◽  
pp. 1533-1546
Author(s):  
Yu. Ye. Gordienko ◽  
S. A. Zuev ◽  
V. V. Starostenko ◽  
V. Yu. Tereshchenko ◽  
A. A. Shadrin
Keyword(s):  
Numerical Simulation ◽  
Simulation Results
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