Faculty Publications
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Item Effect of reduced geometric dimensions on torque generation in two plate rotor magnetorheological brake with in-house magnetorheological fluid(Institute of Physics, 2023) Kariganaur, A.K.; Kadam, S.; Kumar, H.; Arun, M.The present study is aimed to evaluate the torque generation capacity of a two plate rotor magnetorheological (MR) brake using in-house prepared MR fluid. The prepared MR fluids were studied for sedimentation rate at different temperatures and flow characterization at different currents and at specific temperatures. The yield stress of the fluid is explored through Herschel-Bulkley model. The results depict significant increase in sedimentation rate and decrease in yield stress with increase in temperature of the MR fluid. MR brake (model-1) is fabricated after finite element method magnetics exhibit magnetic field of approximately 0.145 T in the shear gap than other two models (model-2 and model-3) considered in this study. Characterization of the MR brake illustrates that there is an increase in torque with increasing current. Further tests have been carried out to identify the effect of sedimentation on torque generation at 52 °C after 15 h of sedimentation. The results indicate 16% reduction in the initial torque because of settling of particles. MR fluid and particles characterization illustrates that 322 °C and 400 °C are critical points in controlling the MR fluid input parameters. © 2023 IOP Publishing Ltd.Item Determining the optimal composition of magnetorheological fluid for a short-stroke magnetorheological damper(Springer, 2023) Aralikatti, S.S.; Puneet, N.P.; Kumar, H.The current study investigates the effect of viscosity of base oil and weight fraction of carbonyl iron particles on maximum yield stress and effective damping range of a short-stroke magnetorheological damper (stroke length of 2 mm) designed for tool vibration mitigation. It is difficult to find the exact composition of magnetorheological fluid (MRF) based on the design equations, as unidentified practical parameters influence their behaviour hence, optimization by experimental techniques is necessary. Optimal composition of MRF are identified by genetic algorithm through central composite design of experiment. A validation study is conducted to cross verify the optimum values delivered by the algorithm. The damper is fitted onto lathe machine with the optimal fluid composition to evaluate its performance in controlling the tool vibration. The damper has been designed for the specific speed, feed and depth of cut however, the design procedure for developing a damper for higher/other cutting conditions can be achieved by the design scheme mentioned in this article. The vibration level of tool reduced by 28.66% and the amplitude of cutting force reduced by 68.18% indicating reduction of chatter vibration with the damper. An improved surface finish has been observed from 4.8 to 1.6 μm. © 2023, Indian Academy of Sciences.Item Study on operational temperature of magneto-rheological fluid and design dimensions of magneto-rheological damper for optimization(Institute of Physics, 2024) Kumar Kariganaur, A.; Kumar, H.; Arun, M.This study aims to restrict the upper limit for flow gap and effective length in magnetorheological (MR) damper for optimal performance. Initially, the sedimentation study of in-house MR fluid (25%) shows that an 8% reduction in the sedimentation ratio with the addition of additive and nonlinear Herschel-Bulkley (HB) model fit reflects a 32.5% decrease in average yield stress with increasing currents when the parallel plate gap is increased from 1 mm to 2 mm. Owing to this decrease in yield stress, further study is extended to fabricate two MR dampers with limit values (LV) of flow gap and effective length with a common magnetic outer cylinder. Testing results of MR dampers revealed a 72% reduction in damping force at 0.8 A current when the LV’s is increased from LV-1 to LV-2. Selecting LV-1 over LV-2 as the upper limit for any design optimization will give the MR damper optimal performance. At higher input parameters, amplitude has a 135% greater impact on damping force than frequency and current. It is also demonstrated that saturation magnetization depends on the applied magnetic field and input loading parameters. Finally, gravimetric analysis shows that the effectiveness of the MR fluid and magnetic particle starts to decline after 322 °C and 400 °C. © 2024 IOP Publishing Ltd.