The resonant valley suppression of a hydraulic shaking table by using adaptive spectral line enhancer

2018 ◽  
Vol 232 (10) ◽  
pp. 1379-1388
Author(s):  
Tao Wang ◽  
Jinchun Song
Keyword(s):  
Spectral Line ◽  
Coupling Effect ◽  
Resonance Effect ◽  
Shaking Table ◽  
Resonance Phenomenon ◽  
Resonant System ◽  
Stability Range ◽  
Elastic Load ◽  
Hydraulic Servo ◽  
The Stability

As an electro-hydraulic servo shaking table takes on an elastic load in a vibration test of a 2-mass dynamic system, a mutual coupling effect is exerted between the shaking table and the specimen, which will form a resonant system to weaken the dynamic characteristics of the system. As required by the system bandwidth, the resonant system contains a resonance valley and a resonance peak, and its amplitude commonly surmounts the stability range of the system’s acceleration amplitude. In this article, the resonance phenomenon is analyzed, and the structure and the parameters of the three-state controller are designed on the basis of a pole assignment system. The adaptive spectral line enhancer is adopted to suppress the resonant valley, and the power spectrum is analyzed to experimentally verify that it exerts an anti-resonance effect.

scholarly journals Resonance Suppression for Hydraulic Servo Shaking Table Based on Adaptive Notch Filter

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Jianjun Yao ◽  
Zhenshuai Wan ◽  
Yue Zhao ◽  
Jie Yu ◽  
Chen Qian ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Notch Filter ◽  
Resonance Mode ◽  
Shaking Table ◽  
Resonance Phenomenon ◽  
Least Mean Square ◽  
Adaptive Notch Filter ◽  
Elastic Load ◽  
Resonance Frequencies ◽  
Hydraulic Servo

In dynamic structure test, the specimen of hydraulic servo shaking table contains not only inertia load but also elastic load. The specimen herein is simplified as a spring-mass-damping system, and the mathematical model of the hydraulic servo shaking table is established by theoretical analysis. The coupling between specimen’s elastic load and shaking table itself produces resonance phenomenon in the required bandwidth when the elastic load is not negligible, which deteriorates the system’s dynamic performance and even leads to the instability of the control system. Also, the time-varying resonance frequency further aggravates the control performance of the system in the shaking test. In this paper, an adaptive notch filter based on least mean square (LMS) error principle is employed to identify the resonance frequencies online and real-time adjust the parameters of the notch filter. Simulation and experiment results show the effectiveness of frequency identification and resonance mode suppression. Compared with the existing resonance suppression scheme, the proposed method can suppress the appeared resonance mode adaptively.

scholarly journals Study on the Resonant Suppression of Electrohydraulic Servo Shaking Table of a 2-Mass Dynamic System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Tao Wang ◽  
Jinchun Song
Keyword(s):  
Dynamic System ◽  
Coupling Effect ◽  
Characteristic Curve ◽  
Notch Filter ◽  
Shaking Table ◽  
Resonant Peak ◽  
Least Mean Square ◽  
Stability Range ◽  
Suppression Effect ◽  
Adaptive Notch Filter

Since the load of electrohydraulic servo shaking table is an elastic load, there is a mutual coupling effect that exists between the experimental object and the shaking table, forming the resonance to weaken the dynamic characteristics, and producing resonant peak and resonant valley in the bandwidth required by the system, in which the amplitude is often larger than the stability range of acceleration’s amplitude. In this paper, the mathematical modeling of hydraulic power mechanism in a two-mass dynamic system is established based on electrohydraulic servo shaking table, yielding the frequency characteristic curve in accordance with the transfer function of the model. A multifrequency adaptive notch filter based on the least mean square algorithm is proposed to suppress the resonance, and the suppression effect of the resonance is simulated and verified in line with various values of load stiffness. Finally, the power spectrum is used to demonstrate the effectiveness of the multifrequency adaptive notch filter in the resonant suppression.

An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

Investigation of the stability of periodic motions in a nonlinear automatic control system based on the fast fourier transform

2003 ◽  
Vol 3 ◽  
pp. 297-307
Author(s):  
V.V. Denisov
Keyword(s):  
Fourier Transform ◽  
Control System ◽  
Automatic Control ◽  
Fast Fourier Transform ◽  
Automatic Control System ◽  
Resonance Phenomenon ◽  
Periodic Motions ◽  
Multiply Connected ◽  
Non Linear ◽  
The Stability

An approach to the study of the stability of non-linear multiply connected systems of automatic control by means of a fast Fourier transform and the resonance phenomenon is considered.

scholarly journals Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

2003 ◽  
Vol 28 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. T. Adorno ◽  
A. V. Benedetti ◽  
R. A. G. da Silva ◽  
M. Blanco
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Transition Temperature ◽  
Phase Transformations ◽  
Decomposition Reaction ◽  
Phase Decomposition ◽  
Stability Range ◽  
X Ray ◽  
Al Content ◽  
The Stability

The influence of the Al content on the phase transformations in Cu-Al-Ag alloys was studied by classical differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). The results indicated that the increase in the Al content and the presence of Ag decrease the rate of the <FONT FACE=Symbol>b</font>1 phase decomposition reaction and contribute for the raise of this transition temperature, thus decreasing the stability range of the perlitic phase resulted from the b1 decomposition reaction.

scholarly journals Shaking Table Test on Dynamic Response of Bedding Rock Slopes With Weak Structural Plane Under Earthquake

2020 ◽  
Vol 8 ◽  
Author(s):  
Changwei Yang ◽  
Liang Zhang ◽  
Yang Liu ◽  
Denghang Tian ◽  
Xueyan Guo ◽  
...  
Keyword(s):  
Seismic Wave ◽  
Shaking Table Test ◽  
Surface Effect ◽  
Shear Plane ◽  
Shaking Table ◽  
Resonance Phenomenon ◽  
Amplification Coefficient ◽  
Structural Plane ◽  
Bedding Slope ◽  
Elevation Effect

Taking a bedding rock slope with weak structural plane as the prototype, a shaking table test with a similarity ratio of 1:10 is designed and carried out. By analyzing the acceleration and displacement responses at different positions of the slope, the seismic response and instability mechanism of rock bedding slope under different seismic amplitudes, frequencies, and durations are studied. Before the failure of the slope, the rock bedding slope shows an obvious “elevation effect” and “surface effect” under the action of Wenchuan Wolong earthquake wave with different amplitudes. With the increase of the amplitude of the input seismic wave, the elevation effect and the surface effect gradually weaken. When the amplitude of the seismic wave reaches 0.9 g, the rock bedding slope begins to show damage, which demonstrates that the difference of PGA amplification coefficients on both sides of the weak structural plane increases significantly. Compared with the Kobe seismic wave and Wenchuan Wolong seismic wave, the excellent frequency of EL Centro seismic wave is closer to the first-order natural frequency of slope model and produces resonance phenomenon, which leads to the elevation effect of PGA amplification coefficient more significantly. Through the analysis of the instability process of rock bedding slope, it can be found that the failure mechanism of the slope can be divided into two stages: the formation of sliding shear plane and the overall instability of the slope.

scholarly journals Modeling and Designing a Hydrostatic Transmission With a Fixed-Displacement Motor

1998 ◽  
Vol 120 (1) ◽  
pp. 45-49 ◽  
Author(s):  
N. D. Manring ◽  
G. R. Luecke
Keyword(s):  
Order System ◽  
Axial Piston Pump ◽  
Third Order ◽  
Stability Range ◽  
Hydrostatic Transmission ◽  
Control Gain ◽  
Variable Displacement ◽  
Linearized System ◽  
The Stability ◽  
Axial Piston

This study develops the dynamic equations that describe the behavior of a hydrostatic transmission utilizing a variable-displacement axial-piston pump with a fixed-displacement motor. In general, the system is noted to be a third-order system with dynamic contributions from the motor, the pressurized hose, and the pump. Using the Routh-Hurwitz criterion, the stability range of this linearized system is presented. Furthermore, a reasonable control-gain is discussed followed by comments regarding the dynamic response of the system as a whole. In particular, the varying of several parameters is shown to have distinct effects on the system rise-time, settling time, and maximum percent-overshoot.

Vibration of Bending-Torsion Coupled Resonance in a Rotor

2013 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Tadashi Tsuji ◽  
Osami Matsushita
Keyword(s):  
Numerical Simulations ◽  
Natural Frequency ◽  
Torsional Vibration ◽  
Rotational Speed ◽  
Coupling Effect ◽  
The Other ◽  
Resonance Phenomenon ◽  
Horizontal Direction ◽  
Bending Vibration ◽  
Rotor Systems

In certain rotor systems, bending-torsion coupled resonance occurs when the rotational speed Ω (= 2π Ωrps) is equal to the sum/difference of the bending natural frequency ωb (= 2π fb) and torsional natural frequency ωθ(= 2πfθ). This coupling effect is due to an unbalance in the rotor. In order to clarify this phenomenon, an equation was derived for the motion of the bending-torsion coupled 2 DOF system, and this coupled resonance was verified by numerical simulations. In stability analyses of an undamped model, unstable rotational speed ranges were found to exist at about Ωrps = fb + fθ. The conditions for stability were also derived from an analysis of a damped model. In rotational simulations, bending-torsion coupled resonance vibration was found to occur at Ωrps = fb − fθ and fb + fθ. In addition, confirmation of this resonance phenomenon was shown by an experiment. When the rotor was excited in the horizontal direction at bending natural frequency, large torsional vibration appeared. On the other hand, when the rotor was excited by torsion at torsional natural frequency, large bending vibration appeared. Therefore, bending-torsion coupled resonance was confirmed.

scholarly journals Seismic Response of Prestressed Anchors with Frame Structure

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Shuaihua Ye ◽  
Zhuangfu Zhao
Keyword(s):  
Seismic Response ◽  
Shaking Table Test ◽  
Coupling Effect ◽  
Soil Mass ◽  
Calculation Model ◽  
Shaking Table ◽  
Frame Structure ◽  
Dynamic Calculation ◽  
Concentrated Mass ◽  
Linear Spring

Based on the equivalent mass-spring model and considering the coupling effect between creep soil and prestressed anchors, the dynamic calculation model of prestressed anchors with frame structure is established. The soil mass is expressed in the form of concentrated mass. The action of the frame structure on the soil is treated as a parallel coupling of a linear spring and a linear damper, and the free section of the anchor is treated as a linear spring. Considering the creep characteristics, the soil is regarded as a Generalized Kelvin body and the anchoring section of the anchor is regarded as an equivalent spring body, which are coupled in parallel. Considering the effect of slope height, the dynamic calculation model is solved and the seismic response is analyzed. Finally, an engineering example is used to verify the calculation method in this paper, and the results are compared with the shaking table test and numerical simulation. It shows that the calculation model proposed in this paper is safe and reasonable for the seismic design and analysis of the slope supported by prestressed anchors with frame structure.

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