An experimental analysis of vibration induced behaviour in magnetorheological fluids
Résumé
Magneto-rheological fluids (MRF) are commonly applied in MRF brakes and vibration damping. The apparent viscosity dependence with respect to the magnetic field has been addressed in detail in the state of the art. The aim of this paper is to experimentally study the vibration effects on the particle chain-like structures and, as a consequence, the shear stress variation applied to the fluid. Three vibration configurations have been applied to a ferromagnetic cylinder rotating between two magnetic poles filled with MRF a "Z-vibration" where the generated displacement is along the rotation axis of the shearing cylinder, a "θ-vibration", tangential to the cylinder, and an "Rvibration", normal to the cylinder surface. First we focus on the vibration mode characterisation in free air, and then when plunged in the fluid. In a second step, we measure the reactive torque generated on the clutch under different magnetic field intensities with different rotation speeds and vibration amplitudes. It appears that the "R-vibration" configuration is providing the most influence, up to 20% of torque reduction observed at moderate B field. The "Z-vibration" and the "θ- vibration" configurations respectively have less influence on the torque, nevertheless vibrations always tend to decrease the corresponding yield stress in the MRF.
Mots clés
Air
Characterization
Cylinder configurations
Cylinders (shapes)
Energy harvesting
Intelligent materials
Intelligent systems
Magnetic fields
Magnetism
Magnetorheological fluids
Shear flow
Shear stress
Yield stress
Apparent viscosity
Different-magnetic fields
Experimental analysis
Ferromagnetic cylinders
Magneto-rheological fluid
Stress variations
Vibration amplitude
Vibration-damping
Vibration analysis