The Experimental Study of the Magnetic Fluid Damper Based on the Principle of Second-Order Buoyancy

Ding, Yi; Li, De Cai; Wang, Qing Lei; Zhang, Hai Na; Zhang, Zhi Li

doi:10.4028/www.scientific.net/kem.512-515.1459

Cited by 3 publications

(2 citation statements)

References 3 publications

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“…Biomedical applications have also been developed to magnetically modify various types of organic or inorganic materials or microbial cells with magnetic fluids [7,8]. Due to the increased saturation magnetization of magnetic fluids exposed to a magnetic field, the application of magnetic fluids in vibration control and dampers especially have received a great deal of attention [9][10][11]. Magnetic fluids were filled in a U-tube to develop a tuned liquid column damper (TLCD) by Oyamada et al [12].…”

Section: Introductionmentioning

confidence: 99%

Damping Force Modeling and Suppression of Self-Excited Vibration due to Magnetic Fluids Applied in the Torque Motor of a Hydraulic Servovalve

Zhang

Peng

2017

Energies

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Abstract:As a key component of hydraulic control systems, hydraulic servovalves influence their performance significantly. Unpredictable self-excited noise inside hydraulic servovalves may cause instability and even failure. Being functional, with higher saturation magnetization and increased viscosity when exposed to a magnetic field, magnetic fluids (MFs) have been widely used in dampers, sealing, and biomedical treatment. In this paper, magnetic fluids are applied in the torque motor of a hydraulic servovalve to exert damping and resistance for vibration and noise suppression. Construction of the torque motor armature with magnetic fluids is introduced and the forces due to magnetic fluids on the torque motor armature are studied. Based on a bi-viscosity-constituted relationship, a mathematical model of the damping force from magnetic fluids is built when magnetic fluids are filled in the working gaps of the torque motor. Measurements of the properties of an Fe 3 O 4 composite magnetic fluid are carried out to calculate the parameters of this mathematical model and to investigate the influence of magnetic fluids on the vibration characteristics of the armature assembly. The simulated and tested harmonic responses of the armature with and without magnetic fluids show the good suppression effects of magnetic fluids on the self-excited noise inside the servovalve.

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Section: Introductionmentioning

confidence: 99%

Damping Force Modeling and Suppression of Self-Excited Vibration due to Magnetic Fluids Applied in the Torque Motor of a Hydraulic Servovalve

Zhang

Peng

2017

Energies

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“…There are also some other applications of MF such as adaptive mirrors [50][51][52], dampers [53][54][55], even in art and display and so on. In this thesis, we focus on the magneto-optical properties of MF and their applications.…”

Section: Thesis Organizationmentioning

confidence: 99%

Investigation of magneto-optical properties of magnetic fluid for fiber optics applications

Zu¹

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Magnetic fluid (MF) is a novel kind of magneto-optical functional material that possesses diverse magneto-optical properties such as tunable refractive index, birefringence effect, dichroism effect, Faraday effect, field dependent transmission property and so on. It can serve as the magnetically sensitive material playing the key role in magnetic field sensors and magneto-optical devices. There were many reported photonic devices based on MF in the literatures. This thesis focuses on investigating the magneto-optical properties of MF for fiber optics applications. The thesis first reviewed the background knowledge including the MF, optical fibers and optical fiber interferometry. The physical origin of refractive index tunability and birefringence effect of MF are detailedly discussed in preparation for the works in the following Chapters. In the thesis, we have presented three kinds of MF-based magnetic field sensors. The first one is based on the birefringence effect of MF. The MF is inserted into an optical fiber Loyt-Sagnac interferometric configuration in the form of MF film. The sensitivity characteristics of this optical fiber Loyt-Sagnac interferometric configuration are theoretically analyzed and experimentally verified. Finally, a sensitivity of 59.2 pm/Oe is achieved by applying the conclusions drawn from the theoretical analysis to the proposed magnetic field sensing configuration. The second one is based on refractive index tunability of MF and the evanescent field of photonic crystal fiber with air-holes collapse. The evanescent light field interacts with the MF and translates the magnetic field strengths into optical signals. A Mach-Zehnder interferometric configuration formed by cascading two sections of v

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Boundary interface condition of magnetic fluid determines the magnetic levitation force experienced by a permanent magnet suspended in the magnetic fluid

et al. 2018

Physics of Fluids

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The buoyancy experienced by a permanent magnet suspended in magnetic fluid is studied, and the expression for calculating the magnetic fluid buoyancy is derived. The magnetic fluid buoyancy or magnetic fluid levitation force, which can be obtained by calculating the sum of Archimedes levitation force and magnetic levitation force, depends on the boundary interface condition of magnetic fluid. The type of the boundary interface and the pressure over it determine the boundary interface condition, and the dependence of boundary interface condition of magnetic fluid and magnetic fluid levitation force is studied. If the boundary interface of the magnetic fluid is a liquid-gas interface in contact with air, the magnetic fluid levitation force will be equal to the gravity of the magnetic fluid. A sudden change in magnetic fluid levitation force can be seen when the liquid-gas boundary interface of magnetic fluid is broken by the wall of a container. Or, in other words, the emergence of a solid-liquid boundary interface will influence the magnetic fluid levitation force, and the magnitude of the change is proportional to magnetic field intensity over the solid-liquid boundary interface. Once the liquid-gas boundary interface is close to a horizontal plane, the magnitude of magnetic fluid levitation force will reach a relatively stable value. In the experiments, the volume of magnetic fluid, the location of the magnet, and the magnetic particle concentration in magnetic fluid are used to control and change the boundary interface condition of magnetic fluid.

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The Experimental Study of the Magnetic Fluid Damper Based on the Principle of Second-Order Buoyancy

Cited by 3 publications

References 3 publications

Damping Force Modeling and Suppression of Self-Excited Vibration due to Magnetic Fluids Applied in the Torque Motor of a Hydraulic Servovalve

Damping Force Modeling and Suppression of Self-Excited Vibration due to Magnetic Fluids Applied in the Torque Motor of a Hydraulic Servovalve

Investigation of magneto-optical properties of magnetic fluid for fiber optics applications

Boundary interface condition of magnetic fluid determines the magnetic levitation force experienced by a permanent magnet suspended in the magnetic fluid

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