Modeling and Experiment on Active Vibration Control of Hydraulic Excitation System

2012 ◽  
Vol 187 ◽  
pp. 130-133 ◽  
Author(s):  
Hui Xian Zhang ◽  
Ling Xia Miao
Keyword(s):  
Cross Section ◽  
Vibration Amplitude ◽  
Method Of Characteristics ◽  
Active Vibration Control ◽  
Computer Code ◽  
Measured Data ◽  
Vibration Exciter ◽  
Lateral Vibration ◽  
Active Vibration ◽  
Excitation Force

For studying dynamic characteristics of fluid filled pipe under hydraulic excitation force generated actively by a new developed vibration exciter, at first a computer code based on the method of characteristics (MOC) was developed. Then the excitation force calculated by MOC was applied to the corresponding nodes of finite element of pipe, by using Newmark’s method, the dynamic response at every cross section of pipe was obtained. The numerical simulations show that a simple harmonic motion arises at every cross section of the pipe, and the lateral vibration amplitude of every node along the pipe increases as the rising excitation force. In addition, measured data were compared with numerical simulation, which were basically consistent with each other.

Numerical Simulation on Dynamic Analysis for Pipe Vibration Control Based on an Actively Generated Hydraulic Excitation Force

2012 ◽  
Vol 490-495 ◽  
pp. 2328-2332 ◽  
Author(s):  
Juan Wu ◽  
Hui Xian Zhang ◽  
Zi Ming Kou ◽  
Chun Yue Lu
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Method Of Characteristics ◽  
Computer Code ◽  
Vibration Exciter ◽  
Lateral Vibration ◽  
System Pressure ◽  
Excitation Force ◽  
Pulsating Fluid ◽  
Pipe Vibration

In order to study dynamic characteristics of fluid filled pipe under hydraulic excitation force generated actively by a new developed vibration exciter, at first mathematical model of pulsating fluid was established and a computer code based on the method of characteristics (MOC) was developed. Then the excitation force calculated by MOC was forced upon the corresponding nodes of finite element of pipe, meanwhile, the nodes of fluid by MOC were assured to coincide with that of the pipe by the method of finite element (FEM). Finally, using Newmark’s method, the dynamic response at every cross section of pipe was solved. The numerical simulations show that a simple harmonic motion arises at every cross section of the pipe. The lateral vibration amplitude of every node along the pipe increases as the rising system pressure. So, this work is expected to provide some theoretical and exploratory basis for studying two dimensional vibration characteristics of fluid filled pipe.

scholarly journals Dynamic Analysis for Lateral Vibrations of Footbridges under Crowd Based on a Two-Degrees-of-Freedom Model

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Bin Zhen ◽  
Wenbang Qi ◽  
Liang Chang
Keyword(s):  
Time Delay ◽  
Vibration Amplitude ◽  
Degrees Of Freedom ◽  
Measured Data ◽  
Lateral Vibration ◽  
Two Degrees Of Freedom ◽  
Cable Stayed Bridge ◽  
Lateral Vibrations ◽  
Subcritical Hopf Bifurcation ◽  
Manifold Theory

Nakamura’s model is widely used to describe lateral vibrations of a footbridge induced by crowd. The predicted responses of Nakamura’s model were compared with measured data of T-bridge and M-bridge in Japan to demonstrate the validity. However, the predicted responses based on Nakamura’s model almost always were stronger than measured data. Considering that both T-bridge and M-bridge are cable-stayed bridges, it seems to be not precise enough to simplify a cable-stayed bridge as a single degree of freedom system in Nakamura’s model. In this paper, we establish a two-degrees-of-freedom model to describe lateral vibrations of a cable-stayed bridge. The cables have one degree, and the bridge deck has the other. Additionally, in this model we introduce a time delay in interaction between the bridge and pedestrians. By employing the center manifold theory, we find that a subcritical Hopf bifurcation occurs in the two-degrees-of-freedom model. We theoretically and numerically illustrate that the cables and time delay have significant influence on the lateral vibration amplitude of a footbridge under crowd. The appropriate increases of tension in the cables and time delay both can decrease the lateral vibration amplitude. The analysis for the proposed two-degrees-of-freedom model shows that the predicted responses of Nakamura’s model can better agree with the measured date if we take the influence of cables and time delay into account.

A Combination of Fuzzy Logic and Neural Network Algorithms for Active Vibration Control

1996 ◽  
Vol 210 (3) ◽  
pp. 153-167 ◽  
Author(s):  
S-J Huang ◽  
R-J Lian
Keyword(s):  
Neural Network ◽  
Fuzzy Logic ◽  
Vibration Control ◽  
Vibration Amplitude ◽  
Mimo System ◽  
Active Vibration Control ◽  
Lumped Mass ◽  
Network Algorithms ◽  
Neural Network Controller ◽  
Active Vibration

The construction of a dynamic absorber incorporating active vibration control is described. The absorber is a 2 degree of freedom spring-lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources. Both the main mass and the secondary absorber mass were acted on by direct current (d.c.) servo motors, respectively, to suppress the vibration amplitude. In this paper, a new control approach is proposed by combining fuzzy logic and neural network algorithms to control the multi-input/multi-output (MIMO) system. Firstly, the fuzzy logic controller was designed for controlling the main influence part of the MIMO system. Secondly, the coupling neural network controller was employed to take care of the coupling effect and refine the control performance of the MIMO system. The experimental results show that the control system effectively suppresses the vibration amplitude and with good position tracking accuracy.

Study of Active Vibration Control for Flexible Beam’s Vibration

2009 ◽  
Vol 69-70 ◽  
pp. 685-689
Author(s):  
Li Zhang ◽  
Shi Ming Ji ◽  
Yi Xie ◽  
Qiao Ling Yuan
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Vibration Signal ◽  
Piezoelectric Ceramics ◽  
Vibration Exciter ◽  
Resonance Amplitude ◽  
Effective Manner ◽  
Smart Beam ◽  
Loop Feedback ◽  
Active Vibration

The attenuation of structure vibration is very slow when flexible strucure is stirred external force. It seriously affected the life of flexible structure. Smart structures used piezoelectric ceramics as actuators are an effective manner to solve the problem. This paper uses Fiber Bragg Grating (FBG) as sensors and piezoelectric ceramics as actuators to study the active vibration control for the resonance of the smart beam. Two groups of piezoelectric ceramics will be used for vibration exciter and vibration abatement, respectively. The fiber smart beam is excited to a sharp vibration nearby the particular resonance frequency by controlling the frequency of the vibration excitation. The vibration signal is measured by the FBG sensors and the close loop feedback control is fulfilled by the vibration abatement group, and the vibration amplitude of the fiber smart beam is abated. The experiment results show that the resonance amplitude of the beam is obviously abated by adjusting the frequency, amplitude and phase of the vibration abatement circuit.

Active Vibration Control of a Rectangular Flexible Wall of an Empty and Fluid-Filled Tank

2004 ◽  
Author(s):  
S. Carra ◽  
M. Amabili ◽  
R. Ohayon ◽  
P. M. Hutin
Keyword(s):  
Vibration Control ◽  
Vibration Amplitude ◽  
Active Vibration Control ◽  
Deformation Energy ◽  
Water Levels ◽  
Structural Vibration ◽  
Control Input ◽  
Least Mean Square ◽  
Modal Shape ◽  
Active Vibration

A rectangular plate bolted to a thick Plexiglas rectangular container is investigated in the case of empty and water-filled tank. A modal analysis is firstly realized in order to verify the effects of different water levels and of the free surface waves on the modal parameters and on the modal shapes. A filtered-x LMS (least mean square) adaptive feedforward algorithm is then applied to the perturbed system realizing structural vibration control in linear field with a SISO approach. Five piezoelectric PZT actuators apply the secondary control input in a nearly-collocated configuration. Their positioning is based on the knowledge on the deformation energy of the plate. The present study investigates primarily the control of the first vibration mode, but second and third modes are also experimentally studied. Satisfactory reductions (up to about 45 dB on the second mode measured on Channel 4) are reached for vibration amplitude of the three modes investigated in absence of water. For each modal shape, a particular effectiveness of the optimally placed actuators clearly appears. The introduction of water in the tank reduces the effectiveness of control of the first mode (maximum 5.5 dB of reduction of the vibration amplitude), but the five control channels show a more global uniform effectiveness.

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