scholarly journals Vibration Frequency Characteristic Study of Two-stage Excitation Valve Used in Vibration Experiment System

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Yongping WU ◽  
Chengwei XIONG ◽  
Yi LIU ◽  
Jiafei ZHENG ◽  
Mingxuan ZOU
Keyword(s):  
High Frequency ◽  
Rotary Valve ◽  
Two Stage ◽  
Maximum Displacement ◽  
Experiment System ◽  
Oil Supply ◽  
Supply Pressure ◽  
Vibration Experiment ◽  
Working Principle ◽  
Large Flow

To satisfy the demands of higher frequency and amplitude in hydraulic vibration experiment system, the two-stage excitation valve is presented, and a mathematical model of two-stage excitation valve is established after analyzing the working principle of two-stage excitation valve, then the influence of relevant parameters on the displacement of main spool of two-stage excitation valve is studied by using Matlab/Simulink to calculate and analyze. The results show that the displacement of main spool will be smaller with bigger diameter and more secondary valve ports. When the reversing frequency is higher and the oil supply pressure is lower as well as the axial guide width of valve ports is smaller, the maximum displacement of main spool is smaller. The new two-stage excitation valve is easy to adjust reversing frequency and flow. The high frequency can be achieved by improving the rotation speed of servo motor and adding the number of secondary valve ports; the large flow can be realized by increasing the axial guide width of secondary valve ports and oil supply pressure. The result of this study is of guiding significance for designing the rotary valve for the achievement of higher reversing frequency and larger flow.

Study on High Frequency Hydraulic Exciter Based on Rotary Valve Control

2012 ◽  
Vol 490-495 ◽  
pp. 1441-1445 ◽  
Author(s):  
Jian Zhuo Zhang ◽  
Li Zhe Guan ◽  
Kang Kang Li
Keyword(s):  
Mathematical Model ◽  
High Frequency ◽  
Rotary Valve ◽  
Exciting Frequency ◽  
Working Principle ◽  
Relationship Of ◽  
The Mathematical Model ◽  
The Relationship ◽  
Valve Control

A kind of hydraulic exciter based on rotary valve control was studied in this paper, the composition of the exciter and its working principle were introduced, and the mathematical model of the system was established. The characters of the system were simulated using MATLAB. From the results of the simulation, we get the relationship of the amplitude of Vibration oil cylinder between the system’s pressure and the exciting frequency. The results can provide theoretical bases to design the hydraulic exciter.

A novel method for high-frequency non-sinusoidal vibration waveforms with uniaxial electro-hydraulic shaking table based on Fourier series

2020 ◽  
pp. 107754632096171
Author(s):  
He Wang ◽  
Zhen Chen ◽  
Jiahai Huang
Keyword(s):  
Fourier Series ◽  
Vibration Frequency ◽  
High Frequency ◽  
Narrow Range ◽  
Harmonic Distortion ◽  
Shaking Table ◽  
Rotary Valve ◽  
Sinusoidal Vibration ◽  
Supply Pressure ◽  
Novel Method

In this article, a rotary valve is developed to obtain accurate high-frequency sinusoidal vibration waveforms. Then, a uniaxial electro-hydraulic shaking table controlled by a set of parallel rotary valves is constructed, which can superpose the sinusoidal vibration waveforms. The non-sinusoidal vibration waveforms including triangular vibration waveform, rectangular vibration waveform, sawtooth vibration waveform and trapezoidal vibration waveform are generated by adjusting the spool rotation speed based on the Fourier series. The results show that with one rotary valve, the uniaxial electro-hydraulic shaking table can output accurate high-frequency sinusoidal vibration waveforms and the total harmonic distortion is less than 1% at high vibration frequency. Compared with the standard vibration waveform, the error of the generated vibration waveform is very small. For the rectangular vibration waveform and sawtooth vibration waveform, the error is less than 6%, and for the triangular vibration waveform and trapezoidal vibration waveform, the error is less than 3%. The impacts of the working conditions on the error of the generated vibration waveform are very small. The proposed method for the accurate high-frequency non-sinusoidal vibration waveform is very effective and can be applied in high vibration frequency and different load masses. With the increase of the supply pressure, the amplitude of the generated vibration waveforms increases, while the error changes in a rather narrow range. The amplitude can be adjusted by changing the supply pressure with almost no effect on the accuracy of the vibration waveform.

High-Frequency Vibration Response of Metal Honeycomb Sandwich Structure

2009 ◽  
Vol 79-82 ◽  
pp. 1727-1730 ◽  
Author(s):  
Xiao Dong He ◽  
Xiang Hao Kong ◽  
Li Ping Shi ◽  
Ming Wei Li
Keyword(s):  
High Frequency ◽  
Sandwich Structure ◽  
Dynamic Pressure ◽  
Vibration Response ◽  
Element Analysis ◽  
High Frequency Vibration ◽  
Honeycomb Sandwich ◽  
Vibration Experiment ◽  
Aerial Vehicle ◽  
Honeycomb Sandwich Structure

ARMOR TPS panel is above the whole ARMOR TPS, and the metal honeycomb sandwich structure is the surface of the ARMOR TPS panel. So the metal honeycomb sandwich structure plays an important role in the ARMOR TPS, while it bears the flight dynamic pressure and stands against the flight dynamic calefaction. So the active environment of metal honeycomb sandwich structure is very formidable. We have to discuss any extreme situation, for reason of making sure aerial vehicle is safe. And high-frequency vibration is one of active environment. In this paper we have analyzed high-frequency vibration response of metal honeycomb sandwich structure. We processed high-frequency vibration experiment by simulating true aerial environment. Sequentially we operated high-frequency vibration experiment of metal honeycomb sandwich structure with cracks, notches and holes. Then finite-element analysis was performed by way of validating the experiment results. Haynes214 is a good high temperature alloy material of both face sheet and core at present, so we choose it in this paper.

Investigation on a two-stage platform of large stroke for broadband vertical vibration isolation

2018 ◽  
Vol 25 (6) ◽  
pp. 1233-1245 ◽  
Author(s):  
Xiling Xie ◽  
Mingke Ren ◽  
Hongbo Zheng ◽  
Zhiyi Zhang
Keyword(s):  
Vibration Isolation ◽  
Vertical Vibration ◽  
Optical Switches ◽  
Static Properties ◽  
Two Stage ◽  
Maximum Displacement ◽  
Primary Stage ◽  
Low Frequencies ◽  
Attenuation Rate ◽  
Secondary Stage

For the purpose of preventing vibration-sensitive optical switches from malfunction caused by broadband vertical vibration, a novel two-stage vibration isolation platform is proposed. The primary stage is a bellows-type isolator of large stroke and low isolation frequency, and the secondary stage is a small-stroke hybrid isolator composed of bellows and voice-coil actuators. In the primary stage, two pre-compressed horizontal bellows and one vertical bellows are used to counter the weight of the switch and to reduce the total height of the isolator. The static properties of the primary stage are analyzed, and the vibration isolation of the platform is investigated. Numerical results indicate that the two-stage platform is effective in isolating vertical vibration. Experiments are also conducted to verify the performance of the platform. It is exhibited that the transmissibility is less than 0 dB over 2 Hz, and the attenuation rate reaches −35 dB/dec at high frequencies. The frequency range of test is 2–200 Hz, and the maximum displacement is 10 mm at 2 Hz. In the secondary stage, the actuators can substantially suppress the resonance peak, and promote isolation performance at low frequencies.

Design of DDS Based on FPGA Technology

2015 ◽  
Vol 713-715 ◽  
pp. 1031-1033
Author(s):  
Wei Jiang ◽  
Fang Yuan ◽  
Liu Qing Yang
Keyword(s):  
High Frequency ◽  
Simple Structure ◽  
Frequency Synthesizer ◽  
Sine Wave ◽  
Lookup Table ◽  
Frequency Resolution ◽  
Signal Frequency ◽  
Small Delay ◽  
Working Principle ◽  
Output Only

This paper introduces the working principle and structure of direct digital frequency synthesizer. This paper select the technology of lookup table to design DDS because it has many advantages such as less consumption hardware resources, simple structure, output only small delay and so on. As a result, signal generator can produce many waveforms with good stability and high frequency resolution. Finally, test showed that the output wave of triangular signal frequency is greater than 1MHz and the highest sine wave frequency is 30MHz, the value of peak to peak is continuously adjustable in 50mV ~ 4V range. The result of study will provide theoretical guidance for the design of DDS.

Design of High Frequency Fatigue Testing Machine Driven by Piezoelectric Vibrator

2012 ◽  
Vol 220-223 ◽  
pp. 543-548
Author(s):  
Meng Jie ◽  
Hai Feng Xie ◽  
Yan Liu ◽  
Zhi Gang Yang
Keyword(s):  
High Frequency ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Fatigue Property ◽  
Maximum Load ◽  
Load Level ◽  
Piezoelectric Resonance ◽  
Piezoelectric Vibrator ◽  
Plate Spring ◽  
Working Principle

In order to measure the fatigue property of the small and hard brittle components working under conditions of the little amplitude, high frequency force, a novel kind of resonant high frequency fatigue testing machine which is driven by the piezoelectric vibrator (PZT、PLZT or PMN) has been proposed. Firstly, the working principle of the piezoelectric resonance high frequency fatigue testing machine is analyzed, and the dynamic model of the fatigue testing machine is established to get the systemic dynamic characteristics. Then a prototype is designed and produced. Finally, the maximum load on the sample is measured by the test with the machine. The results indicate that the maximum load on the sample is 23.4N-98.1N when changing the voltage (100V-250V) and the thickness of the plate spring (1.1mm-0.6mm). The prototype made in this paper is suitable for the tensile and fatigue testing with the load level mentioned above under the condition of little amplitude and high frequency force.

Differential Drive Servo Valve Based on MSMA

2012 ◽  
Vol 271-272 ◽  
pp. 858-862
Author(s):  
Chao Yu ◽  
Kui Sheng Chen ◽  
Shu Guang Fu
Keyword(s):  
Simulation Analysis ◽  
Structural Features ◽  
Paper Briefly ◽  
Servo Valve ◽  
Differential Drive ◽  
High Frequency Response ◽  
Low Field ◽  
Working Principle ◽  
Large Flow ◽  
The Magnetic Field

Aimed at the contradiction between high frequency response and large flow of servo valve, the paper puts forward a 2D servo valve with differential drive based on magnetic controlled shape memory alloy(MSMA). To realize large flow control, the valve-spool is set of flow increasing orifice to match the flow increasing window on the valve-sleeve. The paper briefly introduces the structural features of the 2D servo valve and the working principle of the differential drive. It also has a simulation analysis on the magnetic field of the drive and the low field of the valve. Simulation results show that, the flow of the valve is linear with the input current.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

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