scholarly journals Analysis and Testing of Chain Characteristics and Rheological Properties for Magnetorheological Fluid

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Song Chen ◽  
Jin Huang ◽  
Hongyu Shu ◽  
Tiger Sun ◽  
Kailin Jian
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Magnetic Particle ◽  
Volume Fraction ◽  
Chain Structure ◽  
Field Size ◽  
Digital Holographic Microscopy ◽  
Mr Fluid ◽  
Shear Yield ◽  
Holographic Microscopy

Digital holographic microscopy is presented in this study, which can measure the magnetorheological (MR) fluid in different volume fractions of particles and different magnetic field strengths. Based on the chain structure of magnetic particle under applied magnetic field, the relationships between shear yield stress, magnetic field, size, and volume fraction of MR fluid in two parallel discs are established. In this experiment, we choose three MR fluid samples to check the rheological properties of MR fluid and to obtain the material parameters with the test equipment of MR fluid; the conclusion is effective.

A New Unified Approach for Flow Analysis of Magneto-Rheological Fluids

Aerospace ◽  
2004 ◽  
Author(s):  
Barkan M. Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang ◽  
Gregory Hitchcock
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Volumetric Flow Rate ◽  
Mr Fluid ◽  
Mason Number ◽  
Universal Approach ◽  
Shear Yield ◽  
Magneto Rheological

The focus of this study is to develop a new universal approach for the flow analysis of magneto-rheological (MR) fluids through channels. An experimental study is conducted to investigate the relationship between the pressure loss of a MR fluid as a function of the applied magnetic field strength, volumetric flow rate, and surface roughness without utilizing the assumption of shear yield stress. A relation for nondimensional friction factor is developed in terms of Mason number and dimensionless surface roughness. It is demonstrated that the pressure loss across the MR fluid flow channel is significantly affected by the magnetic field and the surface roughness.

MAGNETORHEOLOGICAL FLUIDS AND THEIR PROPERTIES

2005 ◽  
Vol 19 (01n03) ◽  
pp. 593-596 ◽  
Author(s):  
J. M. HE ◽  
J. HUANG
Keyword(s):  
Magnetic Field ◽  
Yield Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Applied Magnetic Field ◽  
Magnetorheological Fluids ◽  
Mr Fluid ◽  
Variable Yield ◽  
Mr Fluids

Magnetorheological (MR) fluids are materials that respond to an applied magnetic field with a change in their rheological properties. Upon application of a magnetic field, MR fluids have a variable yield strength. Altering the strength of the applied magnetic field will control the yield stress of these fluids. In this paper, the method for measuring the yield stress of MR fluids is proposed. The curves between the yield stress of the MR fluid and the applied magnetic field are obtained from the experiment. The result indicates that with the increase of the applied magnetic field the yield stress of the MR fluids goes up rapidly.

Microstructure evolution based particle chain model for shear yield stress of magnetorheological fluids

2020 ◽  
Vol 32 (1) ◽  
pp. 49-64
Author(s):  
Yongbo Peng ◽  
Pei Pei
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Magnetorheological Fluids ◽  
Model Verification ◽  
Structure Evolution ◽  
Chain Model ◽  
Shear Model ◽  
Proposed Model

To predict the shear stress of magnetorheological fluids (MRFs) under magnetic field and shear flows, a meso-microscale shear model is proposed based on the entire course of particle aggregates and chains. For this purpose, a systematic study on the microstructure evolution and rheological properties of MRFs is conducted by using molecular dynamics simulations. An efficient chain identification technique is introduced to count the number of particle chains within the suspension system. From the perspective of particle-level simulations, the microstructured behavior of MRFs involving particle aggregation and internal structure evolution of magnetorheological suspensions are addressed. Shear properties of MRFs derived by the proposed model are studied, and model verification by comparison with previous experimental data and predictions of the existing structural viscosity model is included as well. It is revealed that the proposed meso-microscale shear model exhibits satisfactory accuracy and efficiency for describing the rheological properties of MRFs. Besides, the critical factors linked with rheological properties of MRFs such as magnetic field strength, particle volume fraction and shear rate, are analyzed, further demonstrating the applicability of the proposed model in design and optimization of MRFs.

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.

Shear and Squeeze Rheometry of Magnetorheological Fluids

2011 ◽  
Vol 305 ◽  
pp. 344-347 ◽  
Author(s):  
Hong Yun Wang ◽  
Hui Qiang Zheng
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Electrical Current ◽  
Test System ◽  
Compression Stress ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Shear Yield ◽  
The Magnetic Field

The mechanical properties of a magnetorheological (MR) fluid in shearing, compression and shearing after compression have been studied in the magnetic field which is generated by a coil carrying different magnitudes of DC electrical current on a self-constructed test system. The relations of compression stress versus compression strain, yield stress versus compression stress were studied under different magnetic fields. The compressing tests showed that the MR fluid is very stiff at small compressive strains lower than 0.13. The shear yield stress of MR fluids after compression was much stronger than that of uncompressed MR fluids under the same magnetic field. The enhanced shear yield stress of MR fluids can be utilized to design the MR clutch and brake for new structure and will make MR fluids technology attractive for many applications.

scholarly journals Compressions of magnetorheological fluids under instantaneous magnetic field and constant area

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongyun Wang ◽  
Cheng Bi ◽  
Yongju Zhang ◽  
Li Zhang ◽  
Fenfen Zhou
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Magnetic Fields ◽  
Power Law ◽  
Chain Structure ◽  
Influential Factors ◽  
Shear Stresses ◽  
Mr Fluid ◽  
Aggregation Effect ◽  
Yield Shear Stress

AbstractCompressions of magnetorheological (MR) fluids have been carried out under instantaneous magnetic fields. The yield strength of the MR fluid in compressive mode has been derived by assuming that it was a transformed shear flow in Bi-visous model. The compressive stresses have experimentally studied under different magnetic fields, different initial gap distances and different compressive velocities. The nominal yield shear stresses of the compressed MR fluid under different influential factors have been calculated. The compressive stress increased in a power law as the applied magnetic field increased, while it decreased as the initial gap distance and the compressive velocity increased. With the increase of magnetic field, the difference between the nominal yield shear stress curves increased, and the exponents of the power law increased with the increase of the magnetic field strengths. A larger initial gap distance and a lower compressive velocity resulted in a higher nominal yield shear stress under the same instantaneous magnetic field. The achieved results of the nominal yield shear stress with magnetic field seemed to deviate from the prediction of dipole model, and the chain structure aggregation effect, the sealing effect and the friction effect by compression should be considered.

Enhance the Yield Shear Stress of Magnetorheological Fluids

2001 ◽  
Vol 15 (06n07) ◽  
pp. 549-556 ◽  
Author(s):  
X. TANG ◽  
X. ZHANG ◽  
R. TAO
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Yield Stress ◽  
Chain Structure ◽  
Single Chain ◽  
Compression Pressure ◽  
Sem Images ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Yield Shear Stress

To enhance the yield shear stress of magnetorheological (MR) fluids is an important task. Since thick columns have a yield stress much higher than a single-chain structure, we enhance the yield stress of an MR fluids by changing the microstructure of MR fluids. Immediately after a magnetic field is applied, we compress the MR fluid along the field direction. SEM images show that the particle chains are pushed together to form thick columns. The shear force measured after the compression indicates that the yield stress can reach as high as 800 kPa under a moderate magnetic field, while the same MR fluid has a yield stress of 80 kPa without compression. This enhanced yield stress increases with the magnetic field and compression pressure and has an upper limit well above 800 kPa. The method is also applicable to electrorheological fluids.

Correlation Between Microscale Magnetic Particle Distribution and Magnetic-Field-Responsive Performance of Three-Dimensional Printed Composites

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
Lu Lu ◽  
Erina Baynojir Joyee ◽  
Yayue Pan
Keyword(s):  
Magnetic Field ◽  
Polymer Composites ◽  
Magnetic Particle ◽  
Particle Distribution ◽  
Three Dimensional ◽  
Distribution Patterns ◽  
Chain Structure ◽  
Physical Models ◽  
Distribution Data ◽  
Material Distribution

To date, several additive manufacturing (AM) technologies have been developed for fabricating smart particle–polymer composites. Those techniques can control particle distributions to achieve gradient or heterogeneous properties and functions. Such manufacturing capability opened up new applications in many fields. However, it is still widely unknown how to design the localized material distribution to achieve desired product properties and functionalities. The correlation between microscale material distribution and macroscopic composite performance needs to be established. In our previous work, a novel magnetic field-assisted stereolithography (M-PSL) process was developed, for fabricating magnetic particle–polymer composites. In this work, we focused on the study of magnetic-field-responsive particle–polymer composite design with the aim of developing guidelines for predicting the magnetic-field-responsive properties of the composite. Microscale particle distribution parameters, including particle loading fraction, magnetic particle chain structure, microstructure orientation, and particle distribution patterns, were investigated. Their influences on the properties of particle–polymer liquid suspensions and properties of the three-dimensional (3D) printed composites were characterized. By utilizing the magnetic anisotropy properties of the printed composites, motions of the printed parts could be actuated at different positions in the applied magnetic field. Physical models were established to predict magnetic properties of the composite and trigger distance of fabricated parts. The predicted results agreed well with the experimental measurements, indicating the effectiveness of predicting macroscopic composite performance using microscale distribution data, and the feasibility of using the developed physical models to guide multimaterial and multifunctional composite design.

MR Fluid Behavior Under Constant Shear Rates and High Magnetic Fields Over Long Time Periods

Aerospace ◽  
2004 ◽  
Author(s):  
Constantin Ciocanel ◽  
Kevin Molyet ◽  
Hideki Yamamoto ◽  
Sheila L. Vieira ◽  
Nagi G. Naganathan
Keyword(s):  
Magnetic Field ◽  
Shear Rate ◽  
Shear Strain ◽  
Rheological Properties ◽  
Smart Materials ◽  
Shear Stresses ◽  
Mr Fluid ◽  
Shear Rates ◽  
Constant Shear ◽  
Mechanical Devices

MR fluids are smart materials that reversibly change their rheological properties in the presence of a magnetic field. Their capability to support a high range of shear stresses makes them an ideal component of many mechanical devices. However, to be suitable for applications requiring a large number of cycles, e.g. a clutch, the long term behavior of these fluids needs to be thoroughly investigated and well understood. The paper presents a new MR cell design along with a study of the shear rate, shear strain, magnetic field and time influences on the properties and behavior of a MR fluid tested for long periods of time. The MR cell is required to adapt a commercially available rheometer to measure the rheological properties of the fluid. Overall characteristics of the designed MR cell output capability are provided. Constant shear rate tests, two hours in duration, have been performed at shear rates between 0.1 and 200 l/s under magnetic field intensities up to 0.4 T. The rheological measurements indicated that the time, the shear strain and the shear rate influence the fluid’s shear stress magnitude.

Hydrodynamic Modeling of Targeted Magnetic-Particle Delivery in a Blood Vessel

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Huei Chu Weng
Keyword(s):  
Magnetic Field ◽  
Blood Vessel ◽  
Flow Rate ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Volume Fraction ◽  
Hydrodynamic Modeling ◽  
Flow Drag ◽  
Particle Delivery

Since the flow of a magnetic fluid could easily be influenced by an external magnetic field, its hydrodynamic modeling promises to be useful for magnetically controllable delivery systems. It is desirable to understand the flow fields and characteristics before targeted magnetic particles arrive at their destination. In this study, we perform an analysis for the effects of particles and a magnetic field on biomedical magnetic fluid flow to study the targeted magnetic-particle delivery in a blood vessel. The fully developed solutions of velocity, flow rate, and flow drag are derived analytically and presented for blood with magnetite nanoparticles at body temperature. Results reveal that in the presence of magnetic nanoparticles, a minimum magnetic field gradient (yield gradient) is required to initiate the delivery. A magnetic driving force leads to the increase in velocity and has enhancing effects on flow rate and flow drag. Such a magnetic driving effect can be magnified by increasing the particle volume fraction.

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