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The work reports the life-cycle test of flake-shaped particle-based magnetorheological (MR) fluid using the MR brake system and evaluated the performance of brake. The choice of the application is based on the understanding that normal force in this case is zero and the same is not true for other applications. Thus, it will exhibit only shear-induced deformation/degradation of MR fluid properties. The test was performed under a constant magnetic field for 10 5 cycles at 300 rpm. The MR fluid collected after cyclic operation exhibits no change in surface morphology as well as MR properties. Thus, the torque transmission even after this cycle remains the same. This is not the same when commercially available spherical particle-based MR fluid is used. There is a decrement in the torque transmission of MR brake by ~ 30%. The results are discussed on the basis of MR effect and the change in surface morphology of particles. The results confirm that the use of flake-shaped-based MR fluid gives better performance when used for long-term application.

Structural deformation in the low shear rate region that is an undeformed state is investigated for the isotropic and anisotropic magnetic particle–based magnetorheological (MR) fluid. Flow curves were obtained for both MR fluids between 0.1 s −1 and 500 s −1 in the absence and in the presence of magnetic fields. A model to describe the flow behavior over the full shear rate study is proposed. The proposed model accounts for the friction contribution coming from particle-particle as well as particle-carrier interactions of anisotropic particles particularly in flake-shaped particles. The parameters derived from the fit have physical meaning, and it correlates with the observed dependency in rheology study. To get a better understanding of particle-particle friction contribution, magnetic nanoparticles were added in the MR fluid and flow behavior is studied. The study clearly demonstrates the contribution of particle-particle friction on the MR properties. The contribution of particle-carrier friction, due to the shape of the particle, is verified by comparing the result with spherical-shaped particle–based MR fluid.

Use of anisotropic iron particles in the magnetorheological (MR) fluid having a high yield stress is a challenge as it increases the viscosity of the fluid in off-state. In this clause, a novel flake shaped iron powder based MR fluid with high yield stress is synthesized and used in shear mode MR damper (SMMD). MR damper design is optimized using fluid properties and Bingham model. Damping performance of newly synthesized MR fluid damper is at par with the available friction based damper used in front loaded washing machine. The unique feature of this design is minimal volume of the fluid (1.5 ml) required to achieve damping force of 50N. Effect of different volume percentage of particles in MR fluid is evaluated in terms of damping force. Effect of testing parameters like displacement and frequency of excitation on damping force was evaluated. Effect of settling of particle on damper performance is discussed in this work. It shows that the flakes shaped-based MR fluid show better stability against gravity. The smaller quantity of present flake shaped-based MR fluid will reduce the cost of shear mode damper.