Vibration Suppression Device Having Variable Inertia Mass by MR-Fluid

2011 ◽  
Author(s):  
Taichi Matsuoka
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Vibration Suppression ◽  
Experimental Results ◽  
Inertia Force ◽  
Test Device ◽  
Piston Cylinder ◽  
New Type ◽  
Vibration Tests ◽  
Force Characteristics

Authors have proposed a new type of vibration suppression device that utilizes variable inertia mass by fluid which acts as a series inertia mass. The series inertia mass is proportional to not only square of a ratio between a diameter of a piston cylinder and a by-pass pipe, and also a density of the fluid. The resisting force characteristics in case of water or turbine oil were measured. To confirm the proposed theory and investigate effects of vibration control, vibration tests of frequency response and seismic response of one-degree-of-freedom system with the test device were carried out. The experimental results were compared with the calculated results, and the effects of vibration suppression are confirmed experimentally and theoretically. In this paper, in order to derive the effect of a variable inertia mass by using a magnet-rheological fluid, resisting force characteristics of the test device are measured in several cases of magnetic field. The orifice of the by-pass pipe can be changed in virtual, since some rare-earth magnets are installed around the by-pass pipe. It can be seen from experimental results that the inertia force is increasing as stronger magnetic fields. It is pointed out that the variable inertia mass can be derived since clustered magnetic particles in the by-pass pipe act as a virtual orifice under strong magnetic field. The relation between magnetic flux and variable inertia mass are estimated experimentally.

Experiment Using a Magnetically Controlled Ferrofluid Flow in a Flatplate Laminar Flow System

2014 ◽  
Vol 896 ◽  
pp. 444-447
Author(s):  
Yi Hua Fan ◽  
Liao Yong Lou ◽  
Yu Ming Chen
Keyword(s):  
Magnetic Field ◽  
Laminar Flow ◽  
Magnetic Particles ◽  
Flow System ◽  
Experimental Results ◽  
Carrier Fluid ◽  
Field Coefficient ◽  
Coefficient Of Viscosity ◽  
Relationship Of ◽  
The Magnetic Field

The Phenomenon of a Magnetic Controlled Ferrofluid Flow in the Flat Plate Laminar Flow System is Discussed in this Paper. the Ferrofluid Flow is One Kind of Colloid Mixture, which is Composited by the Magnetic Particles, Carrier Fluid and Surfactant. its Motion is Followed the Fluid Dynamics and can be Controlled by a Magnetic Field. from the Theoretic Analysis and the Experimental Test, the Coefficient of Viscosity of the Ferrofluid Flow will be Affected by the Magnetic Field. Thus, an Experimental Rig is Built to Test the Influences of the Gap of the Plate and the Strength and Direction of the Magnetic Field for Several Ferrofluid Flows with Different Dividing Rates of Volume. Experimental Results Showed that the Coefficient of Viscosity of the Ferrofluid Flow is Almost Not Upgrading in a Wide Gap Condition by the Magnetic Field, but as the Gap is Smaller, the Coefficient of Viscosity will be Promoted Obviously. Furthermore, Enhancing the Magnetic Field, it will be Increase the Coefficient of Viscosity of the Ferrofluid Flow. from the Experimental Results, the Relationship of the Magnetic Field, Coefficient of Viscosity of Ferrofluid Flow and the Carrier Fluid can be Confirmed.

"Magnetoactivated" Elastomer: An Alternative to Electroactive Polymer

2008 ◽  
Vol 144 ◽  
pp. 244-249 ◽  
Author(s):  
Yousef Razouk ◽  
Eric Duhayon ◽  
Bertrand Nogarede
Keyword(s):  
Magnetic Field ◽  
Magnetic Permeability ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Young Modulus ◽  
Electroactive Polymer ◽  
Iron Particles ◽  
Silicon Matrix ◽  
Potential Applications ◽  
New Type

This paper deals with the development of a new type of composites called "magnetoactivated" polymers and the exploration of some of their potential applications. "Magnetoactivated" polymers consist of small embedding (micron-sized) magnetic particles in a high elastic silicon matrix to render it magnetically active and at the same time mechanically strong. The experimental characterizations obtained (magnetic permeability and Young modulus) were systematically compared with the values resulting from the modeling of this material.The elastic properties of our "magnetoactivated" silicon motive us to use them as pump membranes, the evolution of the displacement of the pump membrane with the applied magnetic field were verified in ANSYS and experimentally for various contents of iron particles in the silicon matrix.

Preparation of Ferrofluid Sealing Ship Stern Shaft and Design of its Seal Structure

2011 ◽  
Vol 486 ◽  
pp. 167-170
Author(s):  
En Xia Yang ◽  
He Ping Liu ◽  
Tao Qin
Keyword(s):  
Magnetic Field ◽  
Pressure Drop ◽  
Chemical Method ◽  
Magnetic Particles ◽  
Experimental Results ◽  
Magnetic Intensity ◽  
Pressure Drops ◽  
Water Based ◽  
Additional Magnetic Field

Ferrofluid is prepared with the chemical method in order to seal the ship stern shaft. Three types of ferrofluid are obtained. Their magnetic particles all are Fe3O4, but their base solutions are separately water, oil and fluorine ether oil. Experimental results show that the value of saturated magnetic intensity of oil based ferrofluid is higher than the others, and its seal performance is better. Viscosity and density of fluorine ether oil based ferrofluid are the highest. Under the effect of the additional magnetic field, the pressure drops of water or oil sealed by water based ferrofluid are all lower, but the pressure drop of water sealed by oil based ferrofluid is close to an ideal value. Therefore, it has practical value that oil based ferrofluid is used as sealing liquid of ship stern shaft.

Study on the Rheological Effect Models of Fluid Magnetic Abrasive

2009 ◽  
Vol 416 ◽  
pp. 54-60
Author(s):  
Huan Wu Sun ◽  
Shi Chun Yang
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Surface Roughness ◽  
Experimental Results ◽  
Transition Phenomenon ◽  
New Type ◽  
Rheological Effect ◽  
First Time ◽  
Precision Finishing ◽  
Magnetic Abrasives

The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives which are developed on the basis of the phase transition phenomenon caused by magnetic field. The rheological effect of FMA is the basis to achieve its finishing function, and has a great impact on the finishing capabilities and the final surface roughness. In order to get a better understanding of FMA finishing mechanism, the rheological effect models of FMA are deduced for the first time, the simulations and the experimental results are discussed as well in this paper.

Soft magnetorheological elastomers as new actuators for valves

2012 ◽  
Vol 23 (9) ◽  
pp. 989-994 ◽  
Author(s):  
Holger Böse ◽  
Raman Rabindranath ◽  
Johannes Ehrlich
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Air Flow ◽  
Inhomogeneous Magnetic Field ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Type Device ◽  
New Type ◽  
Flow Through ◽  
The Magnetic Field

The actuation behavior of soft silicone-based magnetorheological elastomers in magnetic fields of variable strength was investigated. An inhomogeneous magnetic field gives rise to a reversible actuation effect, which is the result of the competition between magnetic and elastic forces in the material. Magnetorheological elastomers are capable of performing more pronounced deformations than known rigid actuator materials. In this article, the actuation behavior of magnetorheological elastomer ring-shaped bodies in a valve-type device for the control of an air flow is demonstrated. For this purpose, magnetorheological elastomer rings with different Shore hardness were prepared and used in the valve. In addition to the common isotropic magnetorheological elastomer samples, rings with an anisotropic arrangement of the magnetic particles were also prepared. The actuation of these anisotropic magnetorheological elastomers was compared with that of the isotropic samples. Based on simulations, the inhomogeneity of the magnetic field at the magnetorheological elastomer material which is required for the actuation could be strongly affected by the shape in the design of the magnetic yoke. In this study, the closing characteristics of the valve with different yoke shapes and magnetorheological elastomer materials were evaluated by measuring the dependence of the air flow rate on the magnetic field strength. It is demonstrated that the air flow through the valve can be controlled by the current in the field-generating coil, which yields the base for a new type of magnetic valve.

Liquid Inertia Damper Having a Screw Shaped Piston

2012 ◽  
Author(s):  
Taichi Matsuoka
Keyword(s):  
Liquid Flow ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Nonlinear Damping ◽  
Inertia Force ◽  
Test Results ◽  
Harmonic Frequency ◽  
Damping Force ◽  
Flow Through ◽  
Force Characteristics

In this paper authors propose a liquid inertia damper that has a screw shaped piston in order to have effect of a series inertia mass. The damper consists of a piston and a cylinder, a screw shaped piston. Water is filled in the cylinder. The peripheral gap of the screw can act as an orifice of a by-pass pipe, and an inertia force is produced by a liquid flow through the gap. In order to confirm the inertia force, a test damper is manufactured, and resisting force characteristics are measured. It is apparent from test results that the damper can have a sum of the inertia force and nonlinear damping force. The series inertia mass is depended on a relation between a diameter of the cylinder and a gap of the screw. To confirm the vibration reduction, harmonic frequency response of one-degree-of-freedom system with the liquid inertia damper is calculated. Finally, the effects of vibration suppression are confirmed numerically.

Interaction force between magnetic field and ferromagnetic target: analytical, numerical and experimental study

SIMULATION ◽  
2018 ◽  
Vol 95 (3) ◽  
pp. 209-218
Author(s):  
Paolo Neri
Keyword(s):  
Magnetic Field ◽  
Ferromagnetic Material ◽  
Interaction Force ◽  
Experimental Results ◽  
Fe Model ◽  
Operational Conditions ◽  
Double Curvature ◽  
Magnetic Action ◽  
Parallel Surfaces ◽  
Vibration Tests

In this study, an analytical model and a finite element (FE) model were developed in order to study the force produced by a permanent magnet on a ferromagnetic target. The study was aimed at estimating the magnetic action in order to design an excitation device for vibration tests. The dynamic analysis of rotating structures as compressors’ bladed wheels requires a solicitation that reflects the operational conditions. If the component is made of ferromagnetic material, it is possible to use magnetic fields for the excitation. The present paper reports the interaction between planar parallel surfaces, first studied analytically and numerically, and the results were compared with experimental results. Then the interaction between sloping surfaces was analyzed, allowing an analytical boundary loss model to be developed. Finally, the FE model was improved to study the interaction between double curvature surfaces. A comparison with experimental results measured on an actual bladed wheel was performed.

Analysis of magneto rheological elastomers for energy harvesting systems

2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé
Keyword(s):  
Magnetic Field ◽  
Energy Harvesting ◽  
Shear Strain ◽  
Magnetic Induction ◽  
Magnetic Particles ◽  
Homogeneous Magnetic Field ◽  
Electrical Signal ◽  
Harvesting Systems ◽  
Dc Bias ◽  
Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

scholarly journals Optical Imaging of Magnetic Particle Cluster Oscillation and Rotation in Glycerol

2021 ◽  
Vol 7 (5) ◽  
pp. 82
Author(s):  
River Gassen ◽  
Dennis Thompkins ◽  
Austin Routt ◽  
Philippe Jones ◽  
Meghan Smith ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Barium Hexaferrite ◽  
Optical Microscope ◽  
Simplified Model ◽  
Particle Cluster ◽  
Average Deviation ◽  
Cross Sectional

Magnetic particles have been evaluated for their biomedical applications as a drug delivery system to treat asthma and other lung diseases. In this study, ferromagnetic barium hexaferrite (BaFe12O19) and iron oxide (Fe3O4) particles were suspended in water or glycerol, as glycerol can be 1000 times more viscous than water. The particle concentration was 2.50 mg/mL for BaFe12O19 particle clusters and 1.00 mg/mL for Fe3O4 particle clusters. The magnetic particle cluster cross-sectional area ranged from 15 to 1000 μμm2, and the particle cluster diameter ranged from 5 to 45 μμm. The magnetic particle clusters were exposed to oscillating or rotating magnetic fields and imaged with an optical microscope. The oscillation frequency of the applied magnetic fields, which was created by homemade wire spools inserted into an optical microscope, ranged from 10 to 180 Hz. The magnetic field magnitudes varied from 0.25 to 9 mT. The minimum magnetic field required for particle cluster rotation or oscillation in glycerol was experimentally measured at different frequencies. The results are in qualitative agreement with a simplified model for single-domain magnetic particles, with an average deviation from the model of 1.7 ± 1.3. The observed difference may be accounted for by the fact that our simplified model does not include effects on particle cluster motion caused by randomly oriented domains in multi-domain magnetic particle clusters, irregular particle cluster size, or magnetic anisotropy, among other effects.

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