Preparation of Magnetorheological Fluid and Study on Its Rheological Properties

2014 ◽  
Vol 13 (02) ◽  
pp. 1450009 ◽  
Author(s):  
Shreedhar Kolekar
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Magnetorheological Fluid ◽  
Magnetic Flux Density ◽  
Iron Loading ◽  
Iron Particles ◽  
Mr Fluid ◽  
Carrier Fluid ◽  
System Type

The present paper focuses on preparation and process of the magnetorheological (MR) fluid whose carrier fluid is silicone-based oil and its additive is the commercial grease with different concentration of iron particles. General properties of MR fluid are discussed and rheological properties like shear rate, shear stress, viscosity of MR fluid can be found by using cone-and-plate sensor system-type rheometer. The result shows that shear stress as a function of magnetic flux density and viscosity does not strictly scale with iron loading.

scholarly journals The influence of base oil type on the rheological properties of ecological lubricating greases

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (2) ◽  
pp. 127-135
Author(s):  
Rafał Kozdrach ◽  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Measurement Data ◽  
Measuring System ◽  
Rheological Parameters ◽  
Flow Curves ◽  
Lubricating Grease ◽  
Dispersion Phase ◽  
Base Oil

The article presents the results of research on the influence the type of base oil in lubricating compositions has on the rheological parameters of selected lubricants. Vegetable, mineral, and synthetic dispersion phases were used to produce lubricating greases. The modified amorphous silica was used as the dispersed phase. However, as a modifying additive was used a substance containing the antioxidants, corrosion inhibitors, and EP/AW additives. The experiments on rheological properties were carried out using a Physica MCR 101 rotational rheometer (manufactured by Anton Paar), equipped with a diffusion air bearing and connected to a pneumatic supply – an oil-free Jun-Air compressor and air drying block. The device is equipped with a Peltier system for temperature control in the range of –20°C to 200°C and an external thermostatic VISCOTHERM V2 system, working in the temperature range of –20°C to 200°C. The rheometer control and measurement data analysis were performed using Rheoplus software. The tests were carried out using a cone-plate measuring system with a shear rate range of 0.01–100 s-1 at 20°C for lubricating compositions prepared on various oil bases. To evaluate the value of rheological parameters, the results of tests of the dependence between shear stress and shear rate (flow curves) were used. For the theoretical determined on the flow curves, the following rheological models were used: Bingham, Herschel–Bulkley, Casson, and Tscheuschner. The values of the shear stress (yield point) in depending on the type of dispersion phase has changed. This proves that the use of a base oil with the appropriate functional properties does not weaken, but reinforces the spatial structure of a lubricating grease. It has an important meaning when selecting construction parameters when designing a central lubrication system with grease made from a vegetable oil base (Abyssinian oil). The rheological properties of the lubricating grease are influenced by the type of base oil and thickener, any additives in the grease, the production technology of the grease, and the conditions in which it is used. The tests revealed an important influence of the base oil on the rheological parameters that describe the behaviour of lubricating compositions subjected to stresses and strains in a lubricating system.

scholarly journals Analysis of Influence of Temperature on Magnetorheological Fluid and Transmission Performance

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Song Chen ◽  
Jin Huang ◽  
Kailin Jian ◽  
Jun Ding
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Rheological Properties ◽  
Temperature Stability ◽  
Transmission Performance ◽  
Mr Fluid ◽  
Influence Of Temperature ◽  
Study Results ◽  
Influence Of Temperature On ◽  
The Magnetic Field

Magnetorheological (MR) fluid shows different performances under different temperature, which causes so many problems like the reduction of rheological properties of MR fluid under a high temperature condition, the uncontrollability of shear stress, and even failure of transmission; on that basis, the influence of temperature on the performance of MR fluid and the cause of the rise in temperature of MR transmission device are analyzed in this paper; the shearing transmission performance of the MR transmission device under the effect of an external magnetic field and the influence of temperature on the shearing stress and transmission performance are analyzed. The study results indicate that temperature highly influences the viscosity of MR fluid, and the viscosity influences the shear stress of the MR fluid. The viscosity of MR fluid gradually declines when temperature rises from 100°C. Once the temperature exceeds 100°C, the viscosity would increase and the temperature stability would decline. Temperature obviously influences the characteristics of MR transmission, and particularly, highly influences the characteristics of MR transmission once being higher than 100°C. The chaining of the material in the magnetic field is influenced, which causes the reduction of the rheological properties, the uncontrollability of the shear stress, and even the failure of transmission.

RELATION BETWEEN SHEAR STRESS AND SHEARING TIME IN SELECTED LUBRICANT COMPOSITIONS

Tribologia ◽  
2018 ◽  
Vol 279 (3) ◽  
pp. 25-33 ◽  
Author(s):  
Ryszard CZARNY
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Tribological Properties ◽  
Shear Stresses ◽  
Test Results ◽  
Molybdenum Disulphide ◽  
Lithium Grease ◽  
Lubricant Composition ◽  
Rate Test

The paper presents the results of studies of the influence of fillers introduced into lubricating greases on changes in values of shear stresses in resulting lubricant compositions. These fillers were powders of graphite, molybdenum disulphide, and PTFE. They are added to grease to improve their tribological properties. They also impact the rheological properties of lubricating compositions, especially on the course of the shear stress, whose value decreases with the duration of the flow of these compositions. Knowledge of changes in the value of this stress is essential in designing central lubrication systems in which these compositions may be used. Tests were performed on lithium grease without fillers as well as on a composition of this grease with the fillers mentioned above. Measurements were carried out using a Rheotest 2.1 rheometer by changing the shearing time at selected gradients of shear rate. Test results have shown that both the kind of filler and the shearing time have an impact on the value of shear stress in the tested lubricant composition.

scholarly journals Quasi-Static Rheological Properties of Lithium-Based Magnetorheological Grease under Large Deformation

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2431
Author(s):  
Huixing Wang ◽  
Guang Zhang ◽  
Jiong Wang
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Shear Rate ◽  
Field Strength ◽  
Shear Strain ◽  
Rheological Properties ◽  
Large Deformation ◽  
Magnetic Field Strength ◽  
Maximum Yield ◽  
Cyclic Shear

This paper investigates the quasi-static rheological properties of lithium-based magnetorheological (MR) grease under large deformation. Three types of lithium-based MR grease comprising different mass ratios of carbonyl iron (CI) particles and lithium-based grease were prepared. The dependence of the magneto-induced stress–strain curves for MR grease on CI particles content, shear rate, and shear deformation under quasi-static monotonic shear conditions were tested and discussed. The results demonstrate that the shear rate dependence of the maximum yield stress is significantly weakened by the magnetic field, and this weakening is further enhanced as the CI particles content of MR grease increases. In addition, to evaluate and characterize the behavior of the cyclic shear–stress curves of MR grease under quasi-static condition, cyclic shear tests under different controlled conditions, i.e., CI particles content, shear rate, shear strain amplitude, and magnetic field strength, were conduct and analyzed. The magneto-induced shear stress of MR grease with higher CI particles content shows a sharp decrease during the transition from loading to unloading. Moreover, the experiment results also show that the damping characteristics of MR grease are highly correlated with CI particles content, shear strain, and magnetic field strength.

The Influence of Base Oil and Thixotropy on Magnetorheological Property of MRF

2013 ◽  
Vol 320 ◽  
pp. 19-24
Author(s):  
Jian Jian Yang ◽  
Hua Yan ◽  
Zhi De Hu ◽  
Shi Xiang Xu
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Magnetorheological Fluid ◽  
Mineral Oil ◽  
Dispersed Phase ◽  
Zero Field ◽  
Rotational Viscometer ◽  
Base Oil ◽  
Low Shear

Adopting carbonyl iron powder and silicone/mineral oil as suspend phase and dispersed phase separately,and silica, kaolin as lubricant additives,magnetorheological (MR) fluid was prepared by ball milling. The apparent viscosity of base oil and shear stress were measured on a modified rotational viscometer. The experimental results demonstrated that an appropriate viscosity of base oil contributed to the rheology of MRF. Adding a small amount of thixotropy into MRF had little influence on zero-field viscosity, which facilitated the application of MRF to maintain adequate liquidity. Under low shear rate conditions, the shear stress was improved by adding thixotropy to some extent, especially in the mineral oil-based magnetorheological fluid, in which the role of silica was superior to kaolin.

Synthesis and field dependent shear stress evaluation of stable MR fluid for brake application

2017 ◽  
Vol 69 (5) ◽  
pp. 655-665 ◽  
Author(s):  
Lijesh K.P. ◽  
Deepak Kumar ◽  
Harish Hirani
Keyword(s):  
Shear Stress ◽  
Oleic Acid ◽  
Silicone Oil ◽  
Ammonium Hydroxide ◽  
Iron Particles ◽  
Mr Fluid ◽  
Content Type ◽  
Weight Percentage ◽  
Mr Fluids ◽  
Brake Application

Purpose The purpose of this paper is to report on the development of magnetorheological (MR) fluids, having high on-state shear stress/viscosity, low off-state shear stress/viscosity, good redispersibility and stable suspension of carbonyl iron particles, using tetramethyl ammonium hydroxide (TAH) and oleic acid. Design/methodology/approach MR fluids for use in brakes are synthesized using different weight percentages of silicone oil, TAH, oleic acid and iron particles. The effects of TAH and oleic acid are studied. Shear stress is measured as a function of magnetic field on a magneto-rheometer. The images of MR particles settling with time are presented. The test set-up used to evaluate the performance of the MR fluids synthesized for brake application is detailed. Finally, a significant improvement in the MR performance of brakes is reported. Findings The MR fluid having 0.25 Wt.% oleic acid showed low off-state viscosity/shear stress and high on-state viscosity/shear stress. A higher weight percentage of TAH in the MR fluid further reduced the low off-shear stress and increased the high on-state shear stress with better stability. Originality/value Improvement of MR brake performance by adding surfactants like TAH and oleic acid has been the subject matter of several studies in the past, but these studies used a fixed percentage of surfactants in MR fluids. In the present work, the optimum percentage of TAH and oleic acid for an improved braking performance is determined by varying their content in the MR fluid, which has not been reported in any other work thus far.

Measurement of Normal Force in Magnetorheological and Ferrofluid Lubricated Bearings

2011 ◽  
Vol 490 ◽  
pp. 25-32 ◽  
Author(s):  
Józef Salwiński ◽  
Wojciech Horak
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Shear Rate ◽  
Rheological Properties ◽  
Magnetic Fluid ◽  
Preliminary Analysis ◽  
Normal Force ◽  
Magnetorheological Fluid ◽  
Study Results ◽  
Field Action

Preliminary analysis of magnetorheological fluid usability in fluid lubricated bearings has been described in the present study. Results of the study aimed at rheological properties of chosen fluids, which possess magnetic properties (both ferrofluids and magnetorheological fluids) with respect to their application in slide bearings have been presented Preliminary analysis of potential advantages related with the magnetic fluid bearing construction was carried out. Results of measurements of normal force developed within magnetorheological fluid and ferrofluid in result of magnetic field action at various shear rate values have been presented.

scholarly journals Effects of Heating Temperature and Load Weight on Rheological Properties of Waste Plastic Cup

2021 ◽  
Vol 17 (1) ◽  
pp. 39-49
Author(s):  
Halimatuddahliana Nasution ◽  
Winny Winny
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Heating Temperature ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Waste Plastic ◽  
Load Weight ◽  
Increasing Load

Analysis of heating temperature and load weight to the rheological properties of waste plastic cups is very important to gain fundamental understanding of the structure, characteristics, and processability of the material. The samples were tested using melt flow indexer. The heating temperature investigated were 180°C, 190°C, 200°C, 210°C, 220°C and 230°C, and the weight load were 1,875 g, 2,160 g, 2,835 g, 3,035 g and 3,450 g. The results obtained showed that the rheological properties of products such as melt flow index, shear stress and shear rate increased and the viscosity decreased with the increasing of heating temperature and load weight. For higher heating temperatures, the melt flow index, shear stress and shear rate of waste plastic cup increased significantly with the increasing load weight whereas the viscosity of waste plastic cup did not decrease significantly with the increasing load weight.

Application of Magnetorheological Fluid in Bulge Tests of Sheet Metal

2013 ◽  
Vol 873 ◽  
pp. 82-90
Author(s):  
Zhong Jin Wang ◽  
Peng Yi Wang
Keyword(s):  
Rheological Properties ◽  
Sheet Metal ◽  
Metal Forming ◽  
Magnetorheological Fluid ◽  
Dome Height ◽  
Forming Process ◽  
Thickness Strain ◽  
Mr Fluid ◽  
Metal Forming Process ◽  
Flexible Die

Magnetorheological (MR) fluid is a kind of smart material. In this paper, magnetorheological (MR) fluid is applied as a flexible-die, the rheological properties of which can be changed rapidly under a magnetic field, in sheet metal forming process. Bulge tests using a kind of MR fluid, MRF-J01T, are carried out on self-designed experimental device. Stainless steel 1Cr18Ni9Ti combined with different process parameters are adopted to investigate the effect of property of MR fluid on the formability of material tested. The results showed that MR fluid can be utilized successfully as a pressure-carrying medium in sheet forming process. The rheological properties of MR fluid can greatly influence the dome height and thickness strain distribution of specimens.

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