Bingham-papanastasiou and approximate parallel models comparison for the design of magneto-rheological valves

Abstract

Magneto-Rheological Fluids (MRFs) are smart materials whose physical properties can be controlled by an exciting magnetic field. MRFs are described as Bingham plastics with variable magnetic field dependent yield stress. Thanks to their particular features, MRFs have been largely employed to realize controllable power dissipating devices and, among them, regulable valves without moving parts. The most commonly configuration used for MRF based valves consists on fluid flow through an annular duct. The conception of such valves implies to deal with different physics. In particular, the magnetic circuit is usually designed and verified by mean of FE (Finite Element) analysis, while the duct geometry is usually dimensioned using an approximated formula based on fluid flow between parallel plates.In the presented work, a complete and detailed derivation of the analytical model is discussed in order to describe the flow of MRFs through an annulus using an approximate parallel plate geometry. Successively, the Bingham-Papanastasiou regularization is chosen as the mean to accurately describe the continuous non-linear yield stress and shear dependent viscosity of a commercially available MRF and it is then implemented into a FE software. This step allows to built a complete multiphysics problem for the design of MRFs based devices.Results obtained from the analytical model and FE analysis are then compared and the different steps in the proposed approaches are validated.

Experimental and theoretical analyses of material removal in poppet valve magnetorheological finishing

“…Bingham-Papanastasiou model (equation 5) is considered as the viscosity model during simulation study. 30 where ‘ m ’ is regularizing parameter, which regulates the exponential stress growth, ‘ η ’ is apparent viscosity, ‘ γ ˙ ’ is shear rate, ‘ µ ’ is plastic viscosity, and ‘ τ y ’ is yield shear stress. Higher yield stress suggests a greater MR impact of the MRP fluid.…”

“…Higher yield stress suggests a greater MR impact of the MRP fluid. 30,31 Before yielding, the MRP media behaves as a nonlinear elastic solid and has an elastic modulus. 31 In order to get the elastic modulus as a normal stress value, multiply it by the average compressive strain, that is induced by depressing the poppet into the MRP fluid ribbon.…”

Synthesis and Characterization of Nano-Particles Based Magnetorheological Fluids for Brake

“…The response time of the overall device tends to be about 10-20 milliseconds, depending on the magnetic circuit design and the device. Multidisciplinary researches [2][3][4][5][6] on MR fluids have been increased considerably after 1990 due to promising applications coming up on the marketplace. The ability to control by a moderate magnetic field (magnetic induction B less than 1 T) the force or torque transmission in actuators, dampers and robotics components, is a consequence of the attractive magnetorheological behavior of MR fluids.…”