Determination of optimal magnetorheological fluid particle loading and size for shear mode monotube damper

Abstract

Magnetorheological (MR) fluids belong to a class of controllable fluids, and the composition and concentration of its components govern its magnetorheological properties. In this study, an optimum particle loading (or mass fraction) and size of iron particles in MR fluid for use in a shear mode monotube MR damper were determined based on the damping force and off-state viscosity of synthesized MR fluid samples. Initially, the morphological and magnetic properties of carbonyl iron particles were characterized. Six MR fluid samples were prepared composed of combination of three different particle loadings and two sizes of iron particles. Magnetorheological tests were conducted on these samples to determine the flow curves at off-state and on-state magnetic field conditions. Herschel-Bulkley model was used for mathematical representation of flow curves at different magnetic fields and to determine their dynamic yield stress. Further, a shear mode monotube MR damper with accumulator was designed by using optimization technique for desired dynamic range and damping force. Magnetostatic analysis was performed to determine the magnetic field strength generated in the shear gap at different currents. The damping force was calculated for synthesized MR fluids based on their dynamic yield stress corresponding to the magnetic field strength in the shear gap. Analysis of variance was performed to analyse the significance of independent factors on the damping force and off-state viscosity of MRF. The optimal particle loading and size which yielded maximum damping force with minimum off-state viscosity were determined using a multi-objective genetic algorithm.

Synthesis of magnetorheological fluid and its application in a twin-tube valve mode automotive damper

“…The mixing ratio used is 70% by volume of silicone oil and 30% by volume of CIP as this is found to be the ideal ratio for application in an automotive damper. 9 The criteria used for choosing this mixing ratio is the magnitude of the damping force developed for a given amount of current supplied. The yield stress developed by the MR fluid in the presence of a magnetic field increases when the proportion of CIP is increased.…”

“…The force developed due to the field-controlled yield stress (controllable force) F s is found using equation (9). The values of F s thus calculated are tabulated in Table 9.…”

“…The study of MR dampers is multidisciplinary and involves mechanical, hydraulic, and electro-magnetic domains. Acharya et al 9 performed experiments with six different MR fluids having different sizes and loading of iron particles to determine the optimal fluid for the application in a monotube MR damper working in the shear mode. MR dampers explored in most of the available literature were either of monotube-type construction or working in the shear mode of the MR valve.…”

Semi-active vibration control of MRF core PMC cantilever sandwich beams: Experimental study

“…It was observed that the six-layered CGRP-PMC material has high strength and stiffness compared to the two-and four-layered CGRP-PMC material. 17,26,27 The properties of CI p provided by the supplier are provided in Table 3 and that of silicone oil in Table 4. The MRF was characterized using Rheometer (Anton Paar, MCR 702) to determine the rheological properties and results were discussed in authors' previous article.…”

Dynamic behavior of sandwich beams with different compositions of magnetorheological fluid core

“…The effect of constituents of MRF such as particle size, weight fraction of carbonyl iron powder (CIP), base oil viscosity, additives on the performance of MR devices were investigated, such as MR dampers [23,24] MR brakes [25], MR rotary brakes [26] and the optimal composition of MRF which yielded best performance for those MR devices were determined. Romaszko et al [27] determined the vibration characteristics of MR beam filled with two types of commercial MRFs and concluded that weight fraction of iron particles in the fluid has a major effect on the natural frequency and damping coefficient of the beam.…”