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7/27/2019 Theoretical and Experimental Studies on Magnetorheological Fluid Damper With Dc Input
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
610
THEORETICAL AND EXPERIMENTAL STUDIES ON
MAGNETORHEOLOGICAL FLUID DAMPER WITH DC INPUT
Mukund A. Patil1, Swapnil Sapkale
2, Sagar Soni
3, Vijay Sarvaiya
4, Vishal Parekh
5
1, 2,3,4,5
Department of Mechanical Engineering, G. H. Raisoni Institute of Engineering andManagement, Jalgaon
Email:1mech8383@gmail.com
2sapy1111@gmail.com
3sagarsoni.soni@ymail.com
4vijaysarvaiya17@gmail.com
ABSTRACT
A magneto-rheological (MR) fluid brake is a device to transmit torque by the shear force of
an MR fluid. Magnetorheological fluids (MRF) are smart materials consisting of silicon oil
and very small soft-magnetic particles. In a magnetic field, the viscosity and the flow
behaviour of the fluid are considerably changed. MRF damper is a device to give damping by
the shear stress of MR fluids. A MRF damper has the property whose damping changes
quickly in response to an external magnetic field strength. The design method of a new MR
fluid damper is investigated theoretically and the structure is presented. The equation of the
damping by MR fluids within damper is derived to provide the theoretical foundations in the
design of the damper. Based on this equation, after mathematical manipulation, the
calculations of the volume, thickness and width of the annular MR fluids within the MR
fluids damper are yielded and discussed.
INTRODUCTION
Magneto-rheological fluids can be characterised as controllable fluids. They are
manufactured by suspending ferromagnetic particles in a carrier fluid. The latter is typically
some kind of oil. MR fluids exhibit a change in rheological properties when being exposed to
a magnetic field (this is known as the on-state). Rheology is defined as the study of the
deformation and flow of matter (typically materials such as rubber, molten plastics, magneto-
rheological fluids, blood, paint, etc) under the influence of an applied stress. The rheological
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING ANDTECHNOLOGY (IJMET)
ISSN 0976 6340 (Print)
ISSN 0976 6359 (Online)
Volume 3, Issue 2, May-August (2012), pp. 610-619
IAEME: www.iaeme.com/ijmet.html
Journal Impact Factor (2012): 3.8071 (Calculated by GISI)www.jifactor.com
IJMET
I A E M E
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
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properties of a liquid are the dominant features that can be quantified to characterise its
behaviour. The properties that can be affected are elasticity, plasticity and viscosity. In the
on-state, ferromagnetic particles are magnetically induced and aggregate to form chain-like or
column-like structures parallel to the applied field. Due to this, MR fluids have the ability to
reversibly change from viscous liquids to semi-solids in milliseconds when being exposed to
a magnetic field. This feature enables a rapid response interface between electronic controlsand mechanical systems, making MRF technologies attractive for many applications (e.g.
dampers).
In this paper, the fundamental design method of the MR damper is investigated theoretically.
Bingham model is used to characterize the constitutive behavior of the MR fluids subject to
an external magnetic field strength. The theoretical method is developed to analyze the shear
stress by the MR fluid within the damper. An engineering expression for the shear stress is
derived to provide the theoretical foundations in the design of the damper. Based on this
equation, being algebraically manipulated, the volume and thickness of the annular MR fluid
within the damper is yielded.
OPERATIONAL PRINCIPLE
MR fluid damper is a device to give damping by the shear stress of MR fluid. A MR damper
has the property whose damping changes quickly in response to an external magnetic field
strength. The MR fluid is filled in the working gap between the fixed outer cylinder and inner
cylinder. The inner cylinder moves at a speed V. In the absence of an applied magnetic field,
the suspended particles of the MR fluid cannot restrict the relative motion between the fixed
outer cylinder and inner cylinder. However, in the course of operation, the magnetic flux path
is formed when the electric current puts through the solenoidal coil. As a result, the particles
are gathered to form the chain-like structures, with the direction of the magnetic flux path.
These chain-like structures restrict the motion of the MR fluid, thereby increasing the shear
stress of the fluid. The damper can be achieved by utilizing the shear force of MR fluid. The
damping values can be adjusted continuously by changing the external magnetic field
strength.
THEORETICAL APPROACH TO MR DAMPER DESIGN
The key question in the design of MR fluid damper is to establish the relation between the
damper and the parameters of the structure and magnetic field strength. As the magnetic field
is applied, the damping F developed by MR fluid can be calculated by
22
0
3
12
sgn( )B
K L rL r
F v f vRh h
= + +
.................................... (1)
Where v is the speed of piston; f is friction of piston and cylinder; 0K is a coefficient
(0.81.0); h is the thickness of the annular MR fluid between the piston and outer cylinder.
The value of h can be given by
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
612
h R r= .... (2)
If it is assumed that the value of f is much smaller, Eqns. (1) and (2) can be mathematically
manipulated to yield
32 2
2 BLr v
F L rh
= + ..... (3)
Eqn. (3) shows that the damping developed in the cylindrical MR fluid damper can be divided into a
magnetic field dependent induced yield stress component BF and a viscous component F .
22B BF L r = ........ (4)
32 Lr v
F h
=
... (5)
The total damping F is the sum of BF and F .
The active volume of annular MR fluid in the cylindrical MR damper can be obtained
through the integration the radius of annular MR fluid as follows.
2
R
r
v L rdr = ..................................................................................................................... (6)
Therefore,
2v rLh= . (7)
Eqns. (4) (7) can be manipulated to yield
( )2B
B
B
Fv F v
F
=
....................................................................................................... (8)
Eqns. (4) and (5) can be algebraically manipulated to derive the thickness of annular MR fluid as
follows.
B
B
Fh rv
F
=
.... (9)
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
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Eqn. (9) gives the minimum active MR fluid volume that is necessary within the damper in order to
achieve the desired control damping ratio BF
F
at a given speed v and a specified controllable
dampingB
F .
The length L of the effective length of the MR fluid can be obtained from Eqns. (7) and (9).
The completed assembly of MR damper is as shown in figure 1.
Figure 1 Catia Model of Magnetorheological Damper
EXPERIMENTAL APPROACH TO MR DAMPER
An MR damper is to be analyzed as a 2-D axisymmetric model in ANSYS software package. For a
given current, we can determine the magnetic flux density at the Engine, MR Fluid and the damper
housing.
Figure 2. 2-D Flux Lines around the Electrical Coil
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
614
Figure 2 shows the flux lines around the electrical coil which is placed in the MR damper. It is
concluded that, all the flux lines are passing through the annular part of the MR damper. This annular
part consists of Magnetorheological fluid. Therefore, the required magnetic field in the annular part of
the damper can be obtained.
Figure 3 (a) and (b) shows the magnetic flux density and magnetic fields generated in the electrical
coils. UTM (Universal testing machine) which was used in the testing of the damper was capable of
both compressive and tensile testing of the sample.
Figure 4 shows the experimental set up for testing of the MR damper. The compression test has been
carried out for testing the force and current characteristics of the damper.
(a) (b)Figure 3. (a) Magnetic flux density and (b) magnetic fields generated in electrical coil.
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
Figure 4. Experimental set up for testing of MR damper.
Table 1.1 Magnetic induction for different current values
Current (A) Magnetic induction (T)
0.2 0.3108
0.4 0.5884
0.6 0.8511
0.8 1.0844
1.0 1.2596
1.2 1.4325
1.4 1.6047
1.6 1.7768
1.8 1.9488
2.0 2.1207
Table 1.1 shows the magnetic induction values for different current values. It has been concluded that,
as the input DC current increases, the magnetic induction in the MR damper increased. Table 1.2
shows the force exerted by the MR damper for different DC current values. From the table 1.2, it has
been seen that, as the current increases, the force exerted by the MR damper increased.
MR Damper
UTM
Machine
DC Power Supply
Computer
for UTM
Software
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
616
Table 1.2 MR damper exerted force for different current values
Current (A) Force (N)
0.0 26
0.2 28
0.4 29
0.6 32
0.8 42
1.0 60
Figure 5. Force versus displacement characteristics of MR damper for 0.0 A and 0.5v = mm/min
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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 6359(Online) Volume 3, Issue 2, May-August (2012), IAEME
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Figure 8 Force versus displacement characteristics of MR damper for 0.6 A and 0.5v = mm/min
Figure 9 Force versus displacement characteristics of MR damper for 0.8 A and 0.5v = mm/min
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CONCLUSION
Magnetorheological (MR) fluid dampers have provided technology that has enabled effective semi-
active control in a number of real world applications. Because of their simplicity, low input power,
scalability and inherent robustness, such MR fluid dampers are quite promising for civil engineering
applications. The geometric design method of a cylindrical MR fluid damper is investigated
theoretically. The damping developed by MR fluid within the damper under different magnetic fieldstrength conditions is analyzed and tested at the Indian Institute of Technology, Bombay. Theengineering design calculations of the volume, thickness and width of the annular MR fluid within the
damper are derived. The parameters of the thickness and width of the fluid in the damper can becalculated from the equations obtained, when the required mechanical power level, the speed of the
piston, and the desired control damping ratio are specified.
ACKNOWLEDGEMENT
This work was financially supported by a G. H. Raisoni Institute of Engineering and Management,
Jalgaon. I am very thankful to HOD of Mechanical engineering department of Indian Institute of
Technology, Bombay for allowed to do experimental work.
REFERENCES
1. J. D. Carlson, D. M. Catanizarite, K. A. Clair, "Commercial magneto-rheological fluiddevice," Proc. 5th International Conference on ER Fluids, MR Suspensions and Associated
Technology, Singapore, 2857-2865(1996).
2. J. H. Koo, F. D. Goncalves, Mehdi Ahmadian. "Investigation of the response time ofMagnetorheological fluid dampers," Proc. SPIE 5386, 63-71(2004).
3. Satsua Soda, Haruhide Kusumoto, et al., "Semi-active seismic response control of base-isolated building with MR damper," Proc. SPIE 5052, 460-467(2003).
4. Yang G. "Large-scale Magnetorheological fluid damper for vibration mitigation: modeling,testing and control," Notre Dame, Indiana. Ph.D. Dissertation University of Notre Dame,
2001.
5. Unsal M. Semi-active vibration control of a parallel platform mechanism usingMagnetorheological damping. Ph. D. Dissertation: University of Florida; 2006.
6. Jolly M.R., Bender J.W., and Carlson J.D. Properties and applications of commercialMagnetorheological fluids. In: Proceedings of the SPIE fifth annual international symposium
on smart structures and materials: San Diego, CA 1998.
7. Yang G, Spencer Jr. BF, Carlson JD, Sain MK. Large-scale MR fluid Dampers: modeling,and dynamic performance considerations. Engineering Structures 2002; 24(3):30923.
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