PHYSICAL MODELING OF DAMPING CHARACTERISTICS OF MR FLUIDS

2002 ◽  
Author(s):  
JEROME SARRAZIN ◽  
JEROME CLARACQ ◽  
JEAN-PIERRE MONTFORT
Keyword(s):  
Physical Modeling ◽  
Damping Characteristics ◽  
Mr Fluids

PHYSICAL MODELING OF DAMPING CHARACTERISTICS OF MR FLUIDS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2704-2710
Author(s):  
JEROME SARRAZIN ◽  
JEROME CLARACQ ◽  
JEAN-PIERRE MONTFORT
Keyword(s):  
Experimental Data ◽  
Physical Modeling ◽  
Magnetic Force ◽  
Viscoelastic Behavior ◽  
Complex Shear Modulus ◽  
Mechanical Spectroscopy ◽  
Viscous Forces ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Complex Shear

The behavior of MR fluids involved in industrial devices is often modeled by analogical models which do no link the parameters with the physical properties of the fluid. From the equations of fluid mechanics, we give a physical meaning to parameters such as friction, elastic and mass coefficients used in the mentioned models. The predictions are checked with experimental data which mimic the behavior of devices such as antiseismic systems. The viscoelastic behavior of MR fluids is characterized by mechanical spectroscopy. The complex shear modulus G *(ω) contains all the information about the restoring and viscous forces. For example, the relation between elastic modulus, yield stress and magnetic force is discussed in terms of strain amplitude.

EVALUATIONS OF CLUSTER STRUCTURE AND MAGNETO-RHEOLOGY OF MR SUSPENSIONS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1437-1442 ◽  
Author(s):  
HIDEYA NISHIYAMA ◽  
KAZUNARI KATAGIRI ◽  
KATSUHISA HAMADA ◽  
KAZUTO KIKUCHI ◽  
KATSUHIKO HATA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cluster Formation ◽  
Cluster Structure ◽  
Mr Damper ◽  
Magnetic Flux Density ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Equivalent Damping Coefficient ◽  
Particle Shapes

In the present study, we sysnthesize two types of MR fluids with different particle shapes and sizes. The magnetic functions are evaluated circulatingly by the analysis of cluster formation, rheological properties in the applied magnetic field and damping characteristics in the MR damper, comparing with those of commercial MR fluids. Final objective is to provide the fundamental data for the development of newly advanced MR fluids. The main topics consist of geographycal cluster formation depending on particle shapes and sizes, relating to the apparent viscosity and yield stress with magnetic flux density and further equivalent damping coefficient of two newly sysnthesised MR fluids comparing with those of LORD MR fluid.

DAMPING CHARACTERISTICS OF MR FLUIDS IN LOW MAGNETIC FIELDS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 829-836 ◽  
Author(s):  
HIDEYA NISHIYAMA ◽  
TADAMASA OYAMA ◽  
TOYOHISA FUJITA
Keyword(s):  
Magnetic Fields ◽  
Flat Plate ◽  
Phase Difference ◽  
Magnetic Fluid ◽  
Cluster Formation ◽  
Cluster Structure ◽  
Viscous Drag ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Viscous Drag Force

The cluster structure is visualized and the physical properties of new two types of nano MR fluids are measured in the applied magnetic fields. Correlating to these measurements, the damping characteristics of an oscillating flat plate immersed in two types of nano MR fluids such as damping amplitude, phase difference, viscous damping coefficient and viscous drag force acted on a flat plate are experimentally clarified, comparing with those of commercial magnetic fluid from the fluiddynamic points of view. It is shown that the resonance of damping amplitude and phase difference are very sensitive to the applied magnetic field, and further the damping effect of MR fluid is about ten times stronger than that of the commercial magnetic fluid even in low magnetic fields of 50–100 Gauss due to the robust cluster formation.

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