APPLICATION OF THE MR LIQUIDS IN SEMI-ACTIVE CONTROL DEVICES

2003 ◽  
Vol 03 (01) ◽  
pp. 55-70 ◽  
Author(s):  
ALESSANDRO BARATTA ◽  
OTTAVIA CORBI
Keyword(s):  
Magnetic Field ◽  
Stress State ◽  
Control Systems ◽  
Carrying Capacity ◽  
Structural Control ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Control Devices ◽  
Semi Solid ◽  
Magneto Rheological

Magneto-rheological liquids are controllable liquids that under the action of a magnetic field can reversibly pass from the linear viscous liquid state with free-flow to the semi-solid one with a controlled stress-state. They are composed of typically non-colloidal magnetic micronized particles and possess a load carrying capacity higher than other, more controllable, fluids, such as electro-rheological liquids; moreover they are less sensitive to impurities and contaminations that may possibly occur in manufacturing. in the paper, the most suitable models for simulation of such devices are investigated with emphasis on evaluation of their efficiency as structural control systems.

Analysis of Magneto Rheological Fluid Journal Bearing

2019 ◽  
Vol 895 ◽  
pp. 152-157 ◽  
Author(s):  
B. Narasimha Rao ◽  
A. Seshadri Sekhar
Keyword(s):  
Magnetic Field ◽  
Newtonian Fluid ◽  
Carrying Capacity ◽  
Smart Materials ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Carrying Capacity ◽  
Mr Fluid ◽  
Load Carrying ◽  
Magneto Rheological

Magneto Rheological (MR) fluids are a class of smart materials where the shear stress is not directly proportional to rate of shear. The viscosity of fluid changes as magnetic field changes and hence this phenomenon is very useful in bearing-rotor system for attenuating the vibrations. In the present study the application of MR fluid as lubricant instead of Newtonian fluid in the journal bearing is explored through steady state, dynamic characteristics and stability. MR fluid film has been modeled as per Bingham rheological model. FEM with three node triangular elements has been used to solve the Reynolds equation both for the Newtonian fluid film and MR fluid film. The results show the load carrying capacity in the case of MR fluid journal bearing is higher than that of using the Newtonian fluid. The load carrying capacity increases with the increasing magnetic field for all eccentricity ratios. The results also show better stability of the bearing using MR fluid at higher eccentricity ratios. The unbalance response of the rotor mounted on the journal bearing using MR fluid is also estimated to be lower than that of with the Newtonian fluid.

The Application of CFRP Reinforcement Scheme in a Overpass Bridge Reinforcement Engineering

2013 ◽  
Vol 753-755 ◽  
pp. 520-524
Author(s):  
Xin Zhao
Keyword(s):  
Stress State ◽  
Carbon Fiber ◽  
Carrying Capacity ◽  
Shear Load ◽  
Load Carrying Capacity ◽  
Flexural Capacity ◽  
Reinforcement Scheme ◽  
Load Carrying ◽  
Before And After ◽  
Carbon Fiber Polymer

Taking a flyover as the background, this paper compares two reinforcement scheme, and ultimately chooses the paste carbon fiber polymer method to reinforce the bridge. It calculates and analyzes the structure before and after the reinforcement, then compares the stress state , shear load-carrying capacity and flexural capacity. At last ,it evaluates the effect of the paste carbon fiber polymer method and puts forward some suggestions.

scholarly journals The Performance of Squeeze Film between Parallel Triangular Plates with a Ferro-Fluid Couple Stress Lubricant

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Akbar Toloian ◽  
Maghsood Daliri ◽  
Nader Javani
Keyword(s):  
Magnetic Field ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Volume Concentration ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Uniform External Magnetic Field ◽  
Film Characteristics ◽  
The Magnetic Field

The present study aims at investigating a couple stress ferrofluid lubricant effects on the performance of the squeezed film when a uniform external magnetic field is applied. For this purpose, Shliomis ferrohydrodynamic and couple stress fluid models are employed. The considered geometry is parallel triangular plates. The effects of couple stress, volume concentration, and Langevin parameters on squeeze film characteristics including time vs. height relationship and load-carrying capacity are investigated. According to the results, employing couple stress ferrofluid lubricant in the presence of the magnetic field leads to an increased performance of the squeeze film.

The Magnetohydrodynamic Parallel Plate Slider Bearing

1965 ◽  
Vol 87 (3) ◽  
pp. 778-780 ◽  
Author(s):  
D. C. Kuzma
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Carrying Capacity ◽  
Parallel Plate ◽  
Step Function ◽  
Load Carrying Capacity ◽  
Field Profile ◽  
Slider Bearing ◽  
Magnetic Field Profile ◽  
Load Carrying

The effect of a nonuniform applied magnetic field on the operation of a parallel plate slider bearing is investigated analytically. It is found that the optimum magnetic field profile is a step function. This profile increases the load-carrying capacity while decreasing the friction factor. Results indicate that the nonuniform applied magnetic field is definitely superior to the uniform applied magnetic field.

The Magnetohydrodynamic Slider Bearing

1962 ◽  
Vol 84 (1) ◽  
pp. 197-202 ◽  
Author(s):  
William T. Snyder
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Boundary Conditions ◽  
Carrying Capacity ◽  
Load Capacity ◽  
Numerical Data ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Electrically Conducting ◽  
Load Carrying

An analysis is presented of the slider bearing using an electrically conducting lubricant, such as a liquid metal, in the presence of a magnetic field. The solution permits the calculation of the load-carrying capacity of the bearing. A comparison is made with the classical slider bearing solution. It is shown that the load capacity of the bearing depends on the electromagnetic boundary conditions entering through the conductivity of the bearing surfaces. Numerical data are presented for nonconducting surfaces with the emphasis on a comparison between the classical bearing and the magnetohydrodynamic bearing characteristics. It is shown that a significant increase in load capacity is possible with liquid metal lubricants in the presence of a magnetic field.

scholarly journals Numerical Study of Surface Roughness and Magnetic Field between Rough and Porous Rectangular Plates

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ramesh B. Kudenatti ◽  
Shalini M. Patil ◽  
P. A. Dinesh ◽  
C. V. Vinay
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Hartmann Number ◽  
Numerical Study ◽  
Mathematical Formulation ◽  
Load Carrying Capacity ◽  
Parallel Plates ◽  
Load Carrying

This paper theoretically examines the combined effects of surface roughness and magnetic field between two rectangular parallel plates of which the upper plate has roughness structure and the lower plate has porous material in the presence of transverse magnetic field. The lubricating fluid in the film region is assumed to be Newtonian fluid (linearly viscous and incompressible fluid). This model consists of mathematical formulation of the problem with appropriate boundary conditions and solution numerically by finite difference based multigrid method. The generalized average modified Reynolds equation is derived for longitudinal roughness using Christensen’s stochastic theory which assumes that the height of the roughness asperity is of the same order as the mean separation between the plates. We obtain the bearing characteristics such as pressure distribution and load carrying capacity for various values of roughness, Hartmann number, and permeability parameters. It is observed that the pressure distribution and load carrying capacity were found to be more pronounced for increasing values of roughness parameter and Hartmann number; whereas these are found to be decreasing for increasing permeability compared to their corresponding classical cases. The physical reasons for these characters are discussed in detail.

Performance characteristics of journal bearings (porous type): A coupled solution using Hartmann number and roughness parameter

2019 ◽  
Vol 234 (5) ◽  
pp. 668-675
Author(s):  
GK Kalavathi ◽  
FA Najar ◽  
MG Vasundhara
Keyword(s):  
Magnetic Field ◽  
Carrying Capacity ◽  
Hartmann Number ◽  
Slip Surface ◽  
Hydrodynamic Lubrication ◽  
Magnetic Field Effect ◽  
Roughness Parameter ◽  
Load Carrying Capacity ◽  
Integral Forms ◽  
Load Carrying

The influence of magnetic field and roughness factor on long journal (porous) bearing with heterogeneous slip/no-slip surface has been described in this paper. Assumptions of hydrodynamic lubrication theory and Navier slip relation were employed during the investigation, and the generalized Reynolds equation for the oil film pressure was obtained using appropriate boundary conditions and the expressions for pressure distribution and load-carrying capacity as a function of Hartmann number, permeability parameter, roughness parameter, and slip parameter were derived in integral forms. Integrals involved are evaluated by using Simpsons 1/3rd rule and Gauss quadrature 16-point formula in MATLAB code. Christensen stochastic process is adopted to study the roughness behavior. In the present analysis, it has been revealed that there is a noticeable escalation in the load-carrying capacity with the embodiment of magnetic field effect, which enables the journal (rotating part) to levitate inside the domain of bearing (stationary part) that indeed supports the lubricant performance.

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