Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
7 results
Search Results
Item Fault diagnosis of deep groove ball bearing through discrete wavelet features using support vector machine(COMADEM International rajbknrao@btinternet.com, 2014) Vernekar, K.; Kumar, H.; Gangadharan, K.V.Bearings are the most important and frequently used machine components in most of the rotating machinery. In industry, breakdown of such crucial components causes heavy losses. So prevention of failure of such components is very essential. This paper presents an online fault detection of a bearing used in an internal combustion engine through machine learning approach using vibration signals of bearing in healthy and simulated faulty conditions. Vibration signals are acquired from bearing in healthy as well as different simulated fault conditions of bearing. The Discrete Wavelet Transform (DWT) features were extracted from vibration signals using MATLAB program. Decision tree technique (J48 algorithm) has been used for important feature selection out of extracted DWT features. Support vector machine is being used as a classifier and obtained results found with classification accuracy of 98.67%.The advantage of machine learning technique for fault diagnosis over conventional vibration analysis approach has demonstrated in this paper.Item Dynamic analysis and optimization of SiC reinforced Al6082 and Al7075 MMCs(Institute of Physics Publishing helen.craven@iop.org, 2019) Allien, V.J.; Kumar, H.; Desai, V.Composites play a vital role in engineering applications. The main aim of this study was to analyse how addition of SiC will improve the damping properties of metal matrix composites (MMCs). The strengthening of composites depends on physical, mechanical and dynamic factors. In the present study, Al6082 and Al7075 aluminum alloy reinforced with (0, 1, 2, 3, 4, 5, 7.5, 10, 15 and 20) different weight percentages of silicon carbide particles (SiCp) MMCs have been fabricated through stir casting method. The microstructure, density, hardness, tensile strength, impact strength, natural frequencies and damping ratio of the MMCs were determined. The mechanical tests and free vibration analysis results revealed that the addition of SiCp reinforcement enhanced the strength and stiffness of the aluminum alloy MMCs. Multi-attribute decision making (MADM) techniques like analytic hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) methods were applied for determining the best fabricated MMCs. Based on MADM techniques, 15% SiC/Al7075 composite was selected as the best material and using response surface methodology (RSM) 13.66% SiC/Al7075 composite was found as the optimal composite material. © 2019 IOP Publishing Ltd.Item Semi-active vibration control of MRF core PMC cantilever sandwich beams: Experimental study(SAGE Publications Ltd info@sagepub.co.uk, 2020) Allien, J.V.; Kumar, H.; Desai, V.The semi-active vibration control of sandwich beams made of chopped strand mat glass fiber reinforced polyester resin polymer matrix composite (PMC) and magnetorheological fluid (MRF) core were experimentally investigated in this study. Two-, four- and six-layered glass fiber reinforced polyester resin polymer matrix composites were prepared using the hand-layup technique. The magnetorheological fluid was prepared in-house with 30% volume of carbonyl iron powder and 70% volume of silicone oil. Nine cantilever sandwich beams of varying thicknesses of the top and bottom layers glass fiber reinforced polyester resin polymer matrix composite beams and middle magnetorheological fluid core were prepared. The magnetorheological fluid core was activated with a non-homogeneous magnetic field using permanent magnets. The first three modes, natural frequencies and damping ratios of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams were determined through free vibration analysis using DEWESoft modal analysis software. The amplitude frequency response of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams through forced vibration analysis was determined using LabVIEW. The effect of various parameters such as magnetic flux density, thickness of glass fiber reinforced polyester resin polymer matrix composite layers and magnetorheological fluid core layer on the natural frequencies, damping ratio and vibration amplitude suppressions of the glass fiber reinforced polyester resin polymer matrix composite-magnetorheological fluid core sandwich beams was investigated. Based on the results obtained, 2 mm thickness top and bottom layers glass fiber reinforced polyester resin polymer matrix composite and 5 mm thickness magnetorheological fluid core sample have achieved a high shift in increased natural frequency, damping ratio and vibration amplitude suppression under the influence of magnetic flux density. © IMechE 2020.Item Free vibration analysis and selection of composite for high strength and stiffness using multi-attribute decision making(Walter de Gruyter GmbH, 2021) Allien, V.; Kumar, H.; Desai, V.This paper describes the optimal selection of chopped strand mat glass-fiber-reinforced unsaturated polyester resin (CGRP) polymer matrix composite (PMC) by considering the strength and stiffness of various composite samples. The two-, four-, six-, eight- and ten-layered CGRP-PMC samples were prepared by using a hand-layup method. Then, the natural frequency and damping ratio of the CGRP-PMC samples were determined through experimental free vibration analysis using DEWESoft software. The density, tensile strength, flexural strength, impact strength, absorbed energy, inter-laminar shear strength, and fracture toughness results of the CGRP-PMC samples were considered as attributes for the selection of the optimal composite using multi-attribute decision making (MADM) techniques. The six-layered CGRP-PMC material was selected as the optimal PMC based on the results of MADM techniques. © 2021 Walter de Gruyter GmbH, Berlin/Boston, Germany 2021.Item Tool vibration isolation in hard turning process with magnetorheological fluid damper(Elsevier Ltd, 2023) Aralikatti, S.S.; Kumar, H.Tool vibration in metal cutting significantly influences the surface finish and machining stability. Suppressing the tool vibration to enhance the finished product quality is the need of the hour. The current study proposes the augmentation of a Magnetorheological (MR) fluid damper to suppress tool vibration in hard tuning with easy installation without structural modification. The MR fluid damper changes its damping coefficient with the magnetic field to regulate variable cutting conditions. An optimal composition of MR fluid has been prepared in-house to be used in the damper. The in-house MR fluid is compared with commercial MR fluid. The comparison shows that in-house prepared MR fluid performs equally well compared to commercial fluid. The MR damper effectively damps high-amplitude vibration at aggressive cutting conditions. The L9 Taguchi design of the experiment opted to arrive at minimal machining parameters to evaluate the damper's performance in machining two workpiece materials, namely oil-hardened nickel steel (OHNS) and high carbon high chromium (HCHCR D2) die steel. The surface roughness and tool vibration are reduced with the damper. It is noted that in-house MR fluid performed equally well as commercial MR fluid. The tool wear study is also carried out to monitor the influence of external damping over tool life. The stability lobe diagram is obtained analytically with experimental validation to mark the stability limit of the machining condition. The stability boundary increases with the damper enabling aggressive cutting conditions. © 2023 The Society of Manufacturing EngineersItem Experimental and Analytical Evaluation of an Acceleration-Based Semiactive Control Strategy for Automotive Suspension Systems with Magneto-Rheological Damper(SAE International, 2023) Jamadar, M.E.H.; Devikiran, P.; Kumar, H.; Joladarshi, S.Most of the control strategies presented to date are based on either the velocities or displacement of the vehicle body and the wheel which are derived by filtering and converting the data from the accelerometer. This increases the computational load and therefore directly affects the performance of the semiactive suspension system. This study presents a control strategy purely based on the acceleration for semiactive control of vehicle suspension with a magneto-rheological MR damper. The effectiveness of the acceleration-based skyhook (ASH) control strategy is compared with the existing velocity-based skyhook (VSH) control strategy based on the vibration response of a single-degree-of-freedom (SDOF) system. The effectiveness of ASH is evaluated experimentally, and the reaction time is evaluated analytically. The experimental results revealed that the ASH reduces the peak displacement and peak acceleration of the mass under the free vibration test and also improves the settling time as compared to VSH. The amplitude of the displacement and acceleration was also found to be reduced under the forced vibration test with maximum improvement observed during high-frequency excitation. The reaction time of ASH was also found to be considerably lower than VSH. Therefore, it was learned that the proposed ASH performed better under high-frequency excitation than under lower-frequency excitation. Moreover, the lower reaction time of the ASH could improve the overall performance of the semiactive suspension system. © 2023 SAE International.Item Design and Development of Internal Wound Magnetorheological Elastomer Mount for Structural Vibration Isolation(Springer, 2025) Bhat, S.H.; Saroj, A.A.; Kumar, H.; Arun, M.; Vaidyanathan, R.V.Vibration isolation of structures is crucial for enhancing reliability when subjected to mechanical vibrations and shocks. This research investigates the application of Magneto-Rheological Elastomer (MRE) mounts to mitigate vibrations in a 15 kg structure. A unique MRE mount with internal windings was designed and developed using magneto-static analysis with maximizing magnetic flux density across MRE through the Design of Experiments (DoE). MRE samples were prepared considering 20, 40 and 60% (wt.) carbonyl iron particle (CIP) content within a silicon elastomer matrix and analyzed under a rheometer. Further, these MRE samples were considered for forced vibration studies with structures placed on MRE mounts across different frequencies. Repeated experiments with all in-house MRE samples demonstrated that the MRE mount significantly mitigated vibrations at different currents and compositions. The transmissibility plot revealed a maximum amplitude reduction of 3.73 times for the 60% MRE sample. These results underscore the importance of optimizing MRE mount and CIP content for effective vibration isolation, which is vital for prolonging the operational lifespan of critical structures. © The Institution of Engineers (India) 2025.