Faculty Publications

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  • Item
    Design of magneto-rheological brake for optimum dimension
    (Springer Verlag service@springer.de, 2018) Lijesh, L.; Kumar, D.; Gangadharan, K.V.
    Online control of braking performance of magneto-rheological (MR) brake by bridling the apparent viscosity of MR fluid and by amending magnetic field is considered as an effective and smart option to replace the conventional disc brake. The magnetic field procreated by electromagnet in MR brake is reliant on dimensions and material properties of MR brake (casing, rotor and MR fluid region). Extensive works have been reported on enhancing the magnetic properties of MR fluid to achieve maximum braking performance; however, scarce works are available that reflects that the dimensions of MR brake influence the braking performance. Prior works on MR brakes focus on designing for meticulous outer dimensions of brakes, and thus, their results find little utility to a new designer. Therefore, the objective of the present work is to propose a methodology to determine the dimension of MR brake for a given outer dimensions, which shall provide maximum braking performance. The, braking performance is evaluated by assessing the effective torque and brake density. Magneto-static analysis using ANSYS is employed for determining the magnetic field in the MR region, and thereafter, the braking torque is calculated. From the obtained results, curve fit equations are proposed to estimate the values of (i) MR brake casing thickness, (ii) height of the MR brake to rotor, (iii) thickness of core, and (iv) thickness of MR fluid region, for achieving maximum torque. To validate the proposed methodology, MR brake with two different electromagnets and rotors is developed. The static performance of MR brake is evaluated by measuring the braking torque for different currents using a torque wrench and the dynamic performance of the MR brakes is performed on an MR brake test setup. The dynamic performance is evaluated by measuring viscous torque. Finally, the comparisons of the theoretical and experimental results are performed and the obtained results are presented. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.
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    Tribological Behaviour of Graphite-Reinforced FeNiCrCuMo High-Entropy Alloy Self-Lubricating Composites for Aircraft Braking Energy Applications
    (Springer New York LLC barbara.b.bertram@gsk.com, 2019) Prabhu, T.R.; Arivarasu, M.; Chodancar, Y.; Arivazhagan, N.; Cadambi, G.; Mishra, R.K.
    In the present study, the graphite-reinforced FeNiCrCuMo high-entropy alloy-based self-lubricating composites are fabricated through the powder metallurgy. The sintering temperatures (900 and 1000 °C) are varied to study the densification and properties of the composites. The composites are characterized for microstructure, density, and hardness. The brake performance of the composites is evaluated for the braking condition of a military aircraft. The microstructure consists of two phases: one phase (lamella structure) rich with the Fe, Cr, C, and Cu and another white phase rich with the Ni, Cu, C, and Fe along with the uniformly distributed graphite. The EDS analysis confirms the presence of Fe, Cr, Ni, Cu, and Mo in the matrix. The composite sintered at 1000 °C shows improved densification, high hardness, high wear resistance, and excellent braking performance. With the increase of braking energy (speed), the wear rate increases due to the increased intensity of abrasive wear, oxidation wear, and plastic deformation-assisted wear, whereas the friction coefficient has not changed much. Low porosity content and mild abrasive wear are responsible for the high wear resistance in the composite sintered at 1000 °C. Compared to the C/C, C/SiC C/C/SiC composites and Fe- or Cu-based composites, the high-entropy alloy-based composites show great potential for improved braking properties in the high-energy braking applications. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
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    Experimental investigation of rotor wound multi disc magneto-rheological fluid brake
    (SAGE Publications Ltd, 2025) Bhat, S.H.; A, A.; Naveen, S.; Kumar, H.; M, A.
    Magneto-Rheological fluid (MRF), known for changing properties under a magnetic field, is ideal for brakes and dampers in magnetically controlled devices. This research presents a novel design for a 10-disc MR brake using in-house Magneto-Rheological Fluid (MRF), distinguished by its integration of electromagnet windings directly onto the brake shaft. Magneto-static analysis, performed using Finite Element Method Magnetics (FEMM) software, optimized the material selection and dimensions, enhancing the magnetic field distribution across the MRF gap and maximizing braking torque. The design, with rotor windings and a consistent MRF gap, generates a uniform magnetic field, significantly boosting performance. Theoretical braking torque was estimated using Bingham plastic model for MRF characterization, aligning well with experimental results. The compact 10-disc MR brake design, weighing 1.19 kg, shows robust torque performance across varying current levels. Remarkably, prior research had not integrated electromagnet windings directly on the rotor of MR brake, marking this study as pioneering in advancing MR brake performance. © The Author(s) 2025.