Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
18 results
Search Results
Item Dynamic characteristics of drilling spindle supported by radial permanent magnet bearings(Elsevier Ltd, 2020) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.This paper presents the drilling spindle dynamic and harmonic characteristics supported by radial permanent magnet bearings (PMBs). Initially, multi-ring radial PMB is designed in proportionate to the dimensions of drilling spindle using Coulombain model and vector approach. Dynamic analysis of spindle is carried out for three different combinations between conventional angular contact bearings (ACBs) and PMBs. First, the spindle was supported by only ACBs. Second, ACBs were completely replaced by radial PMBs and one ACB was used in between two PMBs making it as a hybrid bearing set (HBS) in the last case. The effect of bearing preload, bearing span and cutting force on the spindle natural frequency, harmonic frequency and critical speed of drilling spindle system was investigated through rotor dynamic analysis. This analysis focuses on the feasibility of successful usage of HBS in drilling machine spindles with higher critical speeds and maximum amplitudes produced due to chattered vibrations and tangential cutting forces. © 2019 Elsevier Ltd.Item Dynamic and harmonic analysis of pillar drilling machine spindle supported by hybrid bearing set(American Institute of Physics Inc. subs@aip.org, 2020) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.The objective of this work is to study the dynamic and harmonic response behavior of drilling spindle supported by hybrid bearing set (HBS). HBS consists of an angular contact bearing (ACB) and radial permanent magnetic bearing. Dynamic and harmonic analysis was performed in order to investigate the effect of bearing stiffness and thrust force on the natural frequency, critical speed and vibration amplitude of a drilling spindle system. In the first step, analyses were carried out for the spindle system supported by conventional ACB's considering the effective bearing span length. In the second step, the dynamic and harmonic responses were analyzed for the drilling spindle system supported by HBS by replacing conventional ACB's. The dynamic performance of spindle under ACB's and HBS is investigated systematically using Ansys rotor dynamic and harmonic response tool. This research highlights the feasibility of effective usage of HBS in drilling machine spindles with higher critical speeds and maximum amplitudes generating due to cutting forces. © 2020 Author(s).Item Evaluation of Dynamic Characteristics of a VMC Spindle System Through Modal and Harmonic Response. Part 1: Spindle Supported by Angular Contact Ball Bearings(Springer Science and Business Media Deutschland GmbH, 2021) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.Machine spindle dynamic characteristics are precisely related to the operation and stability of the machining process. The finite element analysis (FEA) has been used to find out the dynamic behavior of spindle-bearing system. The unbalance response of the vertical machining center (VMC) spindle system at the cutting tool due to thrust force is calculated to study the dynamic properties. In this paper, Ansys Workbench rotordynamic and harmonic response have been used to make the dynamic investigation of VMC spindle and estimate the final values. Results show that the obtained critical speeds are nowhere near to the spindle operating speed range; hence, the resonance would not occur, and at operating speed, the maximum unbalance response is within an acceptable limit. The effect of rotordynamic and harmonic response on same VMC spindle system supported by hybrid bearing set is analyzed in Part 2 as an extension of this work. © 2021, Springer Nature Singapore Pte Ltd.Item Evaluation of Dynamic Characteristics of a VMC Spindle System Through Modal and Harmonic Response—Part 2: Spindle Supported by Hybrid Bearing Set(Springer Science and Business Media Deutschland GmbH, 2021) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.This paper extends the proposed dynamic analysis of spindle with conventional bearings of Part 1 and demonstrates feasibility of hybrid bearing set (HBS) usage in machine tool spindles. HBS consists of permanent magnet bearing (PMB) and conventional angular contact bearing (ACB). The rotordynamic and unbalance response of vertical machining center (VMC) spindle supported by HBS is presented. Harmonic responses are also determined using Ansys Workbench finite element tool. Results show that the system is stable at obtained frequencies, critical speeds are higher than the spindle operating speed range, and the maximum unbalance response is within acceptable limit. The comparison between the results of ACB and HBS has verified that the HBS can effectively be used in machine tool spindles with higher critical speeds and maximum amplitudes generating due to cutting forces. © 2021, Springer Nature Singapore Pte Ltd.Item Friction-free permanent magnet bearings for rotating shafts: A comprehensive review(Electromagnetics Academy, 2020) Bekinal, S.I.; Doddamani, M.This article presents a comprehensive review of modeling, analysis, and development of permanent magnet bearings (PMB) for rotating shafts. The different configurations of PMB are highlighted with relevant approaches to estimate their features. The progress in mathematical approaches adopted and optimization of the static and dynamic bearing characteristics in terms of accuracy are discussed in depth. Further, key developments on instability issues and their realization in combination with other bearings for rotors stability in low and high-speed applications are reviewed. Finally, concluding remarks on key aspects to be followed in the design and development of PMB are presented. © 2020, Electromagnetics Academy. All rights reserved.Item A Review of Superconducting Magnetic Bearings and Their Application(Institute of Electrical and Electronics Engineers Inc., 2022) Supreeth, D.K.; Bekinal, S.I.; Shivamurthy, S.R.; Doddamani, M.Magnetic bearings are being researched for high-speed applications, such as flywheel energy storage devices, to eliminate friction losses. As per Earnshaw's theorem, stable levitation cannot be achieved for a static passive magnetic bearing system. Fully passive stable levitation can be achieved with the help of superconducting magnetic bearings (SMB). This article provides an in-depth review of the modeling, analysis, and development of SMB. The different SMB configurations are highlighted, together with essential methodologies for estimating and improving their performance. The advancements in mathematical models used and the optimization of bearing characteristics are thoroughly discussed. Further, key developments in the application of SMB in flywheel energy storage systems are also reviewed. © 2002-2011 IEEE.Item Utilization of low computational cost two dimensional analytical equations in optimization of multi rings permanent magnet thrust bearings(Electromagnetics Academy chew@jpier.org Suite 207777 Concord Avenue Cambridge, MA 02138, USA 02138 Massachusetts, 2017) Bekinal, S.I.; Doddamani, M.; Dravid, N.D.Replacement of conventional bearings by passive magnetic bearings for high-speed applications, in terms of their performance will be effective, if the design is carried out by optimizing the geometrical dimensions in the given control volume. Present work deals with modification and utilization of two-dimensional (2D) analytical equations in optimization of multi rings permanent magnet (PM) thrust bearing configurations. Conventional and rotational magnetized direction (RMD) configurations are selected in optimizing the design variables for maximum bearing characteristics in a given volume with a constant aspect ratio. The design variables chosen for optimization are axial offset of rotor, number of rings, radial air thickness and inner diameter of the rotor and stator PM rings. MATLAB codes for solving 2D equations are developed in optimizing configuration variables. Further, optimized parameter values of the two configurations are compared. Finally, optimized results obtained using 2D and three-dimensional (3D) equations for the conventional configuration with same aspect ratio are compared, and conclusions are presented. © 2017, Electromagnetics Academy. All rights reserved.Item Optimization of Axially Magnetized Stack Structured Permanent Magnet Thrust Bearing Using Three- Dimensional Mathematical Model(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2017) Bekinal, S.I.; Doddamani, M.; Jana, S.This work deals with optimization of axially magnetized stack structured permanent magnet (PM) thrust bearing using generalized three-dimensional (3D) mathematical model having "n" number of ring pairs. The stack structured PM thrust bearing is optimized for the maximum axial force and stiffness in a given cylindrical volume. MATLAB codes are written to solve the developed equations for optimization of geometrical parameters (axial offset, number of ring pairs, air gap, and inner radius of inner and outer rings). Further, the results of proposed optimization method are validated using finite element analysis (FEA) and further, generalized by establishing the relationship between optimal design variables and air gap pertaining to cylindrical volume constraint of bearing's outer diameter. Effectiveness of the proposed method is demonstrated by optimizing PM thrust bearing in a given cylindrical volume. Mathematical model with optimized geometrical parameters dealt in the present work helps the designer in developing PM thrust bearings effectively and efficiently for variety of applications. © 2017 by ASME.Item A Pragmatic Optimization of Axial Stack-Radial Passive Magnetic Bearings(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2018) Lijesh, L.; Doddamani, M.; Bekinal, S.I.Passive magnetic bearing's (PMB) adaptability for both lower and higher speed applications demands detailed and critical analysis of design, performance optimization, and manufacturability. Optimization techniques for stacked PMB published in recent past are less accurate with respect to complete optimum solution. In this context, the present work deals with a pragmatic optimization of axially stacked PMBs for the maximum radial load using three-dimensional (3D) equations. Optimization for three different PMB configurations, monolithic, conventional, and rotational magnetized direction (RMD), is presented based on the constraints, constants, and bounds of the dimensions obtained from published literature. Further, to assist the designers, equations to estimate the mean radius and clearance being crucial parameters are provided for the given axial length and outer radius of the stator with the objective of achieving maximum load-carrying capacity. A comparison of the load-carrying capacity of conventional stacked PMB using the proposed equation with the equation provided in literature is compared. Finally, effectiveness of the proposed pragmatic optimization technique is demonstrated by analyzing three examples with reference to available literature. © 2018 by ASME.Item 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.