Browsing by Author "Tomar, Adesh Kumar"

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    Combined Effect of Surface Irregularities and Applied Voltage on the Behavior of Hole-Entry Spherical Hybrid Journal Bearings Lubricated With an Electro-Rheological Fluid
    (2024) Tomar, Adesh Kumar; Sahu, K.; Sharma, S. C.; Marian, Max
    Surface irregularities substantially affect the performance of tribological systems. The influence of three-dimensional surface irregularities on the behavior of hole-entry spherical hybrid journal bearings has been investigated. Recently, smart fluids have been employed in several applications to improve their performance. The interactive effect of electrorheological (ER) fluid and surface irregularities has also been studied. The modified Reynolds equation and restrictor flow equation have been solved using the finite element technique with appropriate boundary conditions. The results show that consideration of surface irregularities on the bearing surface enhances bearing stability. Spherical hybrid journal bearings lubricated by ER fluid increase minimum fluid film thickness and minimize the possibility of metal-to-metal contact. It is found that the combined effect of surface irregularities and ER fluid significantly improved the bearing performance parameters than individual behavior. The bearing designer is anticipated to benefit from the current model.
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    Effect of re-melted textured patterns on the mechanical and tribological behavior of 70Mn steel
    (Springer Science and Business Media Deutschland GmbH, 2025) Chen, Yazhe; Shang, Qingyu; Zhang, Youwei; Yao, Ying; Tomar, Adesh Kumar; Long, Risheng; Marian, Max
    © 2025, Emerald Publishing Limited.Purpose: This study aims to investigate the mechanical and tribological behavior of 70Mn steel with different laser re-melted textured patterns. Design/methodology/approach: Laser surface re-melting (LSR) was used to manufacture various textured patterns (i.e. line, grid and mixed) on both the original and heat-treated 70Mn steel plates. The micro-hardness, microstructure, tensile strength, yield strength, elongation, coefficients of friction (COF) and worn morphologies were characterized to evaluate the impact of different textured patterns on the overall performance. Findings: The results show that re-melted unit exhibited the highest surface hardness on the subsurface. The increase in surface hardness of the re-melted unit for the heat-treated 70Mn steel samples was much lower than that of the original ones. The re-melted textured patterns did not improve the tensile strength, yield strength and elongation of either original or heat-treated 70Mn steel samples. The re-melted textured patterns effectively reduced the average COFs of heat-treated 70Mn steel samples, but increased friction of the non-heat-treated samples. Originality/value: This study provides valuable insights into enhancing the mechanical properties and tribological characteristics of 70Mn steel, particularly in the automotive, heavy machinery and high-load application sectors. These industries have stringent requirements for durability and friction control, and the findings of this research are expected to effectively extend the lifespan of mechanical components. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2024-0443/
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    Slot-entry herringbone grooved hybrid conical bearings under piezo-viscous lubrication
    (2025) Tomar, Adesh Kumar; Sahu, Krishnkant; Sharma, Satish C.; Marian, Max
    This study investigates the effect of herringbone groove geometry and piezoviscous shear-thinning fluid (PVSTF) behavior on the performance of slot-entry hybrid conical journal bearings (SHCJBs). Using a modified Reynolds equation solved via finite element analysis and the Gauss–Seidel method, the influence of groove angles (30°, 60°, and 90°), semi-cone angles, and lubricant type on key tribological parameters is examined. The results indicate that a 30° groove angle in combination with PVSTF yields the highest stiffness coefficients and stability margins, while also reducing frictional torque compared to non-grooved designs and Newtonian lubricants. These findings provide design guidance for optimizing bearing geometry and lubricant selection, with applicability to high-performance rotating machinery.