Browsing by Author "Muzakkir, S.M."

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Enhancing tribological performance of Ti-6Al-4V by sliding process
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Kumar, D.; Deepak, K.B.; Muzakkir, S.M.; Wani, M.F.; Lijesh, L.
The exceptional combination of mechanical, physical, and anti-corrosive properties of titanium alloy Ti-6Al-4 V (Ti64) makes it idle material for the applications, e.g., aerospace, automobile, chemical, medical etc. The tribological performance of the Ti64 can be enhanced by developing a protective layer or coating on its surface. A tribo-oxide protective layer on the surface of Ti64 through rubbing process was developed. For this, the tribological behavior of tribo pair, Ti64 pin-alumina disc was studied under dry ambient condition for diverse loading and sliding speed conditions, using pin on disc experimental set-up. The tribological performance was quantified in terms of coefficient of friction and wear rate. The mechanical properties like nano-hardness and elastic modulus of the pins surface were determined. The tribological behavior were extremely transient and depend greatly on what the surface has precisely experienced. Experimental results revealed that deprived tribological properties and higher oxide layer was selected. To enhance the tribological behavior of deprived tribological behavior, the pin with high oxide layer is used.
Multi-objective optimization of stacked radial passive magnetic bearing
(SAGE Publications Ltd info@sagepub.co.uk, 2018) Lijesh, K.P.; Doddamani, M.; Bekinal, S.I.; Muzakkir, S.M.
Modeling, design, and optimization for performances of passive magnetic bearings (PMBs) are indispensable, as they deliver lubrication free, friction less, zero wear, and maintenance-free operations. However, single-layer PMBs has lower load-carrying capacity and stiffness necessitating development of stacked structure PMBs for maximum load and stiffness. Present work is focused on multi-objective optimization of radial PMBs to achieve maximum load-carrying capacity and stiffness in a given volume. Three-dimensional Coulombian equations are utilized for estimating load and stiffness of stacked radial PMBs. Constraints, constants, and bounds for the optimization are extracted from the available literature. Optimization is performed for force and stiffness maximization in the obtained bounds with three PMB configurations, namely (i) mono-layer, (ii) conventional (back to back), and (iii) rotational magnetized direction. The optimum dimensions required for achieving maximum load without compromising stiffness for all three configurations is investigated. For designers ease, equations to estimate the optimized values of load, stiffness, and stacked PMB variables in terms of single-layer PMB are proposed. Finally, the effectiveness of the proposed method is demonstrated by considering the PMB dimensions from the available literature. © IMechE 2017.
Thermal and frictional performance evaluation of nano lubricant with multi wall carbon nano tubes (MWCNTs) as nano-additive
(2018) Lijesh, K.P.; Kumar, D.; Muzakkir, S.M.; Hirani, H.
A Fluid Film Bearings (FFBs) operating in hydrodynamic boundary regime can provide moderate load carrying capacity, negligible wear and friction. However in extreme operating conditions i.e. at high load and low speed, asperities of journal and bearing surfaces come in contact with each other resulting in high wear and friction. During the contact of the asperities, the temperature of the lubricant increases due to frictional heating, resulting in reduction of the viscosity of lubricant. Variation of lubricant viscosity results in low load carrying capacity of the FFB and therefore resulting in detoriation of FFB performance. In the present work it is hypothesized that, by adding multi-functional Multi Wall Carbon Nano-Tubes (MWCNT) (having high thermal conductivity and anti-friction properties) as nano-additive in the base mineral oil, the aforementioned problems can be overcome. To validate the proposed hypothesis, five different samples of lubricant is considered: Sample 1: Base oil, Sample 2: Base oil +0.05% MWCNT, Sample 3: Base oil +0.05% MWCNT +0.5%surfactant, Sample 4: Base oil +0.1% MWCNT +0.5% surfactant, and Sample 5: Base oil +0.15% MWCNT +0.5%surfactant. To evaluate the performance of the developed lubricants, experiments were performed on the reduced scale conformal block on disc test setup. The experimental condition and dimension of the block and disc were decide for the Sommerfeld number equal to 0.0025, which indicates mixed lubrication regime. The performance of lubricant is evaluated by measuring the frictional force and temperature rise of the lubricant during the experiment. � 2018 Author(s).
Thermal and frictional performance evaluation of nano lubricant with multi wall carbon nano tubes (MWCNTs) as nano-additive
(American Institute of Physics Inc. subs@aip.org, 2018) Lijesh, K.P.; Kumar, D.; Muzakkir, S.M.; Hirani, H.
A Fluid Film Bearings (FFBs) operating in hydrodynamic boundary regime can provide moderate load carrying capacity, negligible wear and friction. However in extreme operating conditions i.e. at high load and low speed, asperities of journal and bearing surfaces come in contact with each other resulting in high wear and friction. During the contact of the asperities, the temperature of the lubricant increases due to frictional heating, resulting in reduction of the viscosity of lubricant. Variation of lubricant viscosity results in low load carrying capacity of the FFB and therefore resulting in detoriation of FFB performance. In the present work it is hypothesized that, by adding multi-functional Multi Wall Carbon Nano-Tubes (MWCNT) (having high thermal conductivity and anti-friction properties) as nano-additive in the base mineral oil, the aforementioned problems can be overcome. To validate the proposed hypothesis, five different samples of lubricant is considered: Sample 1: Base oil, Sample 2: Base oil +0.05% MWCNT, Sample 3: Base oil +0.05% MWCNT +0.5%surfactant, Sample 4: Base oil +0.1% MWCNT +0.5% surfactant, and Sample 5: Base oil +0.15% MWCNT +0.5%surfactant. To evaluate the performance of the developed lubricants, experiments were performed on the reduced scale conformal block on disc test setup. The experimental condition and dimension of the block and disc were decide for the Sommerfeld number equal to 0.0025, which indicates mixed lubrication regime. The performance of lubricant is evaluated by measuring the frictional force and temperature rise of the lubricant during the experiment. Â© 2018 Author(s).