Damping properties for vibration suppression in electrohydraulic servo-valve torque motor using magnetic fluid

2014 ◽  
Vol 104 (17) ◽  
pp. 171905 ◽  
Author(s):  
Jinghui Peng ◽  
Songjing Li ◽  
Hasiaoqier Han
Keyword(s):  
Magnetic Fluid ◽  
Vibration Suppression ◽  
Damping Properties ◽  
Servo Valve

Broadband Vibration Suppression Assessment of Negative Impedance Shunts

2008 ◽  
Author(s):  
Benjamin Beck ◽  
Kenneth A. Cunefare ◽  
Massimo Ruzzene
Keyword(s):  
Active Control ◽  
Vibration Suppression ◽  
Piezoelectric Materials ◽  
Input Power ◽  
Experimental Results ◽  
Spatial Average ◽  
Negative Capacitance ◽  
Damping Properties ◽  
Control Solution ◽  
Stiffness And Damping

Piezoelectric materials allow for the manipulation of stiffness and damping properties of host structures by the application of electrical shunting networks. The use of piezoelectric patches for broadband control of vibration using a negative impedance shunt has been shown to be an effective active control solution. The wave-tuning and minimization of reactive input power shunt selection methodologies require the use a negative capacitance. This paper shows that the two theories are comparative and obtain the same shunt parameters. The results of the theoretical shunt selection and simulation are compared to experimental results of tip vibration suppression, spatial average vibration, and reactive input power minimization.

Vibration Control by Active Tuned Liquid Damper Using Magnetic Fluid

1997 ◽  
Author(s):  
Masato Abé ◽  
Yozo Fujino ◽  
Yasuyuki Sano
Keyword(s):  
Magnetic Field ◽  
Vibration Control ◽  
Magnetic Fluid ◽  
Model Building ◽  
Vibration Suppression ◽  
Tuned Liquid Damper ◽  
Base Shear ◽  
Suppression Effect ◽  
Tuned Liquid Dampers ◽  
Dynamic Magnetic Field

Abstract To enhance the performance of tuned liquid dampers (TLD), active TLD which contains magnetic fluid activated by electromagnet is proposed. At the first half of the paper, characteristics of sloshing motion of magnetic fluid subject to dynamic magnetic field is experimentally studied. Sloshing motion and base shear force are found to be effectively controlled by magnetic force. Then, a rule-based control law is constructed and applied to the vibration control of a model building. Vibration suppression effect of passive TLD is improved by applying appropriately scheduled dynamic magnetic field.

Depression of Self-Excited Pressure Oscillations and Noise in the Pilot Stage of a Hydraulic Jet-Pipe Servo-Valve Using Magnetic Fluids

2011 ◽  
Vol 378-379 ◽  
pp. 632-635 ◽  
Author(s):  
Song Jing Li ◽  
Jing Hui Peng ◽  
Sheng Zhuo Zhang ◽  
Jacob M. Mchenya
Keyword(s):  
Magnetic Fluid ◽  
High Frequency ◽  
Pressure Oscillation ◽  
Magnetic Fluids ◽  
Pressure Oscillations ◽  
Servo Valve ◽  
Hydraulic Servo ◽  
Working Principle ◽  
Fft Analysis

Magnetic fluid (MF) shows an increased saturation magnetization when exposed to a magnetic field. In order to improve the quality of servo-valve products by depressing and overcoming the self-excited high-frequency pressure oscillations and noise appearing in pilot stage of a hydraulic servo-valve, application of magnetic fluid in a hydraulic servo-valve is developed in this paper. Large damping can be introduced by the magnetic fluids into the servo-valve if magnetic fluids are filled into the working gaps of the hydraulic servo-valve torque motor. After the construction and working principle of a hydraulic servo-valve with magnetic fluids are introduced, the high-frequency pressure oscillation signals are tested and recorded when magnetic fluids are applied or not in the servo-valve. Experimental results are compared and analyzed by using FFT analysis method. It is shown that pressure oscillations of the servo-valve are depressed when magnetic fluids are applied.

FLEXURAL VIBRATION SUPPRESSION OF GLASS FIBER/CuZnAl SMA COMPOSITE

2012 ◽  
Vol 05 (01) ◽  
pp. 1250014 ◽  
Author(s):  
CARLO ALBERTO BIFFI ◽  
PAOLA BASSANI ◽  
AUSONIO TUISSI ◽  
MARCO CARNEVALE ◽  
NORA LECIS ◽  
...  
Keyword(s):  
Glass Fiber ◽  
Vibration Suppression ◽  
Functional Characterization ◽  
Flexural Vibration ◽  
Thin Sheets ◽  
Damping Properties ◽  
Structural Damping ◽  
Laser Technology ◽  
Martensitic State

This work proposes the functional characterization of a composite material, suitable for passive suppression of flexural vibration of beams and shells. Two patterned thin sheets of CuZnAl Shape Memory Alloy (SMA) are embedded into a layered beam of glass fiber. The composite combines the density and stiffness of the glass fiber with high damping properties of SMA in martensitic state. Properly shaped patterning of the SMA sheets, for improving adhesion between the SMA and glass fiber, is performed by means of laser technology. The effect of the laser micromachining on transformation temperatures and internal friction properties of the SMA elements are analyzed. Finally, measurements of the structural damping of the layered glass fiber/SMA composite are reported and the flexural vibration suppression, due to the embedded CuZnAl sheets, is shown.

scholarly journals Impact of Titanium and Activated Carbon Stabilizers on the Rheological Property of Magnetorheological Fluid during Turning Process

2019 ◽  
Vol 9 (1) ◽  
pp. 4792-4798
Keyword(s):  
Activated Carbon ◽  
Magnetic Fluid ◽  
Metal Cutting ◽  
Magnetic Particles ◽  
Vibration Suppression ◽  
Cutting Speed ◽  
Magnetorheological Fluid ◽  
Turning Process ◽  
Viscosity Change ◽  
Machining Parameter

Vibration has been a major constraint in the machining industries as it has catastrophic effects on the machining parameter. Though there have been several attempts made by the researchers each had their own limitations and constraints. In metal cutting, Magnetorheological fluid (MRF) has proved to be effective in vibration suppression when employed as a semi-active damper. MRF is a smart non-Newtonian fluid which has the capacity to alter its viscosity instantaneously on the application of magnetic field. Along with this property and its robust nature they have used in a wide variety of places as a damper. One major limitation is its settling of magnetic particles which are suspended in a non-magnetic fluid. The settling rate will be further aggravated when the current supplied to coil is increased. Increased current will increase the heat produced in the coil which in turn will heat the non-magnetic fluid wherein its viscosity gets reduced. This problem of settling of iron particles can be prevented by adding stabilizers, similarly the size of particles also has an immediate effect on settling. In the current investigation Titanium and Activated carbon was added as stabilizers to magnetorheological fluid and then the viscosity change brought about in the fluid was studied. Further to support and add clarity to the work variable cutting speed and feed test was also performed. From the experimental results it was evident that stabilizers (activated carbon by 0.1% of weight) in MRF has increased the viscosity and thereby aided in an effective turning process of hardened SS410 steel.

A magnetic super lattice

1987 ◽  
Vol 45 ◽  
pp. 360-361 ◽  
Author(s):  
M.D. Bentzon ◽  
J. v. Wonterghem ◽  
A. Thölén
Keyword(s):  
Thermal Decomposition ◽  
Oleic Acid ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Carbon Film ◽  
Thick Layer ◽  
Amorphous Iron ◽  
Super Lattice ◽  
Carrier Liquid ◽  
Median Diameter

We report on the oxidation of a magnetic fluid. The oxidation results in magnetic super lattice crystals. The “atoms” are hematite (α-Fe2O3) particles with a diameter ø = 6.9 nm and they are covered with a 1-2 nm thick layer of surfactant molecules.Magnetic fluids are homogeneous suspensions of small magnetic particles in a carrier liquid. To prevent agglomeration, the particles are coated with surfactant molecules. The magnetic fluid studied in this work was produced by thermal decomposition of Fe(CO)5 in Declin (carrier liquid) in the presence of oleic acid (surfactant). The magnetic particles consist of an amorphous iron-carbon alloy. For TEM investigation a droplet of the fluid was added to benzine and a carbon film on a copper net was immersed. When exposed to air the sample starts burning. The oxidation and electron irradiation transform the magnetic particles into hematite (α-Fe2O3) particles with a median diameter ø = 6.9 nm.

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