Thermal and tribological performance of graphite flake based magnetorheological fluid under shear mode clutch

2021 ◽  
pp. 1-24
Author(s):  
Manish Kumar Thakur ◽  
Chiranjit Sarkar

Abstract In this research work, graphite flake has been used as an additive in magnetorheological (MR) fluid to improve its thermal and tribological performance. MR fluids with varying amounts of graphite flakes (0.5, 1, 2, 3, 4, and 5 wt%) are prepared to show effective thermal and tribological performance. A test rig is developed with a DC motor, torque sensor, and MR clutch operated in a shear mode to test the torque transmission. Results show the lubrication effects of graphite flakes in MR fluid. Torque transmission is improved in on-state and off-state using graphite flakes based MR fluid as compared to conventional MR fluid. Heating of MR clutch is also reduced with the graphite flakes based MR fluid. Wear marks and damages are decreased significantly with the increased amount of graphite flakes as found in surface roughness tests. SEM and EDS are used to characterize the worn surfaces. This research provides information about the effectiveness of graphite flakes in the MR clutch to improve the device's performance.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Jin Huang ◽  
Ping Wang ◽  
Guochao Wang

Magnetorheological (MR) disk-type isolating dampers are the semi-active control devices that use MR fluids to produce controllable squeezing force. In this paper, the analytical endeavor into the fluid dynamic modeling of an MR isolating damper is reported. The velocity and pressure distribution of an MR fluid operating in an axisymmetric squeeze model are analytically solved using a biviscosity constitutive model. Analytical solutions for the flow behavior of MR fluid flowing through the parallel channel are obtained. The equation for the squeezing force is derived to provide the theoretical foundation for the design of the isolating damper. The result shows that with the increase of the applied magnetic field strength, the squeezing force is increased.


Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni

Magnetorheological (MR) fluids have a lot of applications in the industrial world, but sometimes their properties are not performing enough to meet system requirements. It has been found that in shear mode MR fluids exhibits a pressure dependency called squeeze strengthen effect. Since a lot of MR fluid based devices work in flow mode (i.e. dampers) this paper investigates the behaviour in flow mode under pressure. The system design is articulated in three steps: hydraulic system design, magnetic circuit design and design of experiment. The experimental apparatus is a cylinder in which a translating piston displaces the fluid without the use of standard gear pumps, incompatible with MR fluids. The experimental apparatus measures the MR fluid yield stress as a function of pressure and magnetic field allowing the yield shear stress to be calculated. A statistical analysis of the results shows that the squeeze strengthen effect is present in flow mode as well and the presence of internal pressure is able to enhance the performance of MR fluid by nearly ten times.


2011 ◽  
Vol 239-242 ◽  
pp. 1731-1734 ◽  
Author(s):  
Jian Zuo Ma ◽  
Guo Chao Wang ◽  
Dong Zuo

A magnetorheological (MR) fan clutch is introduced. Based on Herschel-Bulkley model, the equation of transmission torque developed by MR fluids is derived to compute the torque transmission ability in the MR fan clutch. The necessary gap and the need of MR fluid volume between two parallel circular discs of the clutch are carried out. The results indicate that, the transmission torque of the MR fan clutch developed rapidly depend on the yield strength of MR fluid. The necessary gap and the volume for the MR fan clutch can be obtained based on MR fluid properties, the desired control torque ratio, the angular velocity and load torque of the clutch.


2006 ◽  
Vol 128 (5) ◽  
pp. 604-610 ◽  
Author(s):  
Barkan Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Cahit Evrensel ◽  
Alan Fuchs ◽  
George Korol

The design, development, and performance characterization of a magnetorheological (MR) fluid clutch for automotive limited slip differential (LSD) applications is presented in this study. The controllability of MR fluids provides an adjustable torque transmission and slippage for the LSD application. Three-dimensional electromagnetic finite element analysis (FEA) is performed to optimize the magnetic circuit and clutch design. Based on the results obtained from the FEA, the theoretical torque transfer capacity of the clutch is predicted utilizing Bingham-Plastic constitutive model. The clutch is characterized at different velocities and electromagnet electric input currents. Both the torque transfer capacity and the response time of the clutch were examined. It was demonstrated that the proposed MR fluid LSD clutch is capable of transferring controllable high torques with a fast response time.


2012 ◽  
Vol 134 (9) ◽  
Author(s):  
A. Spaggiari ◽  
E. Dragoni

Magnetorheological (MR) fluids are widely used in the industrial world; however, sometimes their properties fail to meet system requirements. In shear mode, MR fluids have been found to exhibit a pressure dependency called squeeze strengthen effect. Since a lot of MR fluid based devices work in flow mode (i.e., dampers), this paper investigates the behavior in flow mode under pressure. The system design consists of three steps: the hydraulic system, the magnetic circuit, and the design of experiment method. The experimental apparatus is a cylinder in which a piston displaces the fluid without the use of standard gear pumps, which are incompatible with MR fluids. The experimental apparatus measures the yield stress of the MR fluid as a function of the pressure and magnetic field, thus, enabling the yield shear stress to be calculated. A statistical analysis of the results shows that the squeeze strengthen effect is also present in flow mode, and that the internal pressure enhances the performance of MR fluids by nearly five times.


Author(s):  
Manish K Thakur ◽  
Chiranjit Sarkar

In this work, the lubrication performance of magnetorheological fluid-filled parallel discs of shear mode magnetorheological clutch is investigated. A magnetorheological fluid contains magnetic particles responsible for the yield strength and hence torque transmission capability in the magnetorheological clutch. The wear damages of magnetic particles of a magnetorheological fluid and magnetorheological clutch discs are examined by scanning electron microscopy and optical microscopy. Energy-dispersive X-ray spectroscopy is used to investigate the variation in chemical composition before and after the experimental test. A test rig is developed to test the torque transmission for a fabricated magnetorheological clutch with a grooved and non-grooved disc. The grooves' impact on both magnetorheological clutch discs' wear and magnetorheological fluid is investigated. It has been observed that the minimum wear damage occurs in the magnetic particles and the disc surface for the circular grooved magnetorheological clutch disc surface than the non-grooved disc surface. An effect of surface texture on the temperature distribution of the magnetorheological clutch is studied through simulation. Simulation results show that the groove's presence on the disc surface can improve the magnetorheological clutch's heat transfer. Hence, the grooved texture improves the lubrication performance and durability of both magnetorheological fluid and magnetorheological clutch.


2012 ◽  
Vol 233 ◽  
pp. 84-87
Author(s):  
Jiu Hua Wang ◽  
Lian Cheng Ren ◽  
Zhen Zhen Lei

A magneto-rheological (MR) fan clutch is a device that transmits torque by the shear stress of the MR fluids. In this paper, Bingham model is used to describe the constitutive characteristics of MR fluids subject to an applied magnetic field. The operational principle of the MR clutch is introduced. The torque transmitted by MR fluids is analyzed to compute the torque transmission ability in the MR clutch. The results show that with the increase of the applied magnetic field, the torque developed by MR fluids goes up rapidly.


2021 ◽  
Vol 8 ◽  
Author(s):  
Honghui Zhang ◽  
Zhiyuan Zou ◽  
Na An ◽  
Ningsong Xiong ◽  
Xu Yang

In light of the insurmountable sedimentation of magnetorheological (MR) fluid, it is of great significance to ensure the performability of an MR damper by introducing a sensing method for MR fluid settling, and a key indicator to identify the health status of the MR damper is critical. However, the settling monitoring system for MR fluid can nowadays only function in a laboratory with transparent and non-magnetic tubes, which is not qualified for the in-situ sensing in a steel-made cylinder. Under the analysis of an open plate capacitor (OPC) configuration, the relationship between the concentration of magnetorheological fluid and the capacitance is investigated by simulation and experiments, and based on OPC, an in-situ sensing method for the settlement monitoring of magnetorheological fluid is designed. Long-time settling monitoring is carried out with home-made MR fluids, and the test results show that the sensing method can effectively reflect the status of settled MR fluids, and has the potential to be utilized in the identification of MR fluid compression points, which provides the strategic signal for the probable active or operational re-dispersing of MR fluid.


Author(s):  
Kwon Joong Son ◽  
Eric P. Fahrenthold

Magnetorheological (MR) fluids, well established as components of a variety of suspension systems, may offer opportunities to improve the performance of fabric ballistic protection systems, which typically do not incorporate significant energy dissipation mechanisms. A series of ballistic impact experiments has been conducted to investigate the potential of MR fluid damped fabric suspension systems to improve upon current fabric barrier designs. The results indicate that for the simple fabric suspension systems tested, MR fluid damping does not improve upon the very high weight specific ballistic performance of state of the art aramid fibers.


Author(s):  
Y K Ahn ◽  
J-Y Ha ◽  
Y-H Kim ◽  
B-S Yang ◽  
M Ahmadian ◽  
...  

This paper presents an analytical and experimental analysis of the characteristics of a squeeze-type magnetorheological (MR) mount which can be used for various vibration isolation areas. The concept of the squeeze-type mount and details of the design of a squeeze-type MR mount are discussed. These are followed by a detailed description of the test set-up for evaluating the dynamic behaviour of the mount. A series of tests was conducted on the prototype mount built for this study, in order to characterize the changes occurring as a result of changing electrical current to the mount. The results of this study show that increasing electrical current to the mount, which increases the yield stress of the MR fluid, will result in an increase in both stiffness and damping of the mount. The results also show that the mount hysteresis increases with increase in current to the MR fluid, causing changes in stiffness and damping at different input frequencies.


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