Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Application of Modeling and Control Approaches of Piezoelectric Actuators: A Review(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Kanchan, M.; Mohith, M.; Bhat, R.; Naik, N.Piezoelectric actuators find extensive application in delivering precision motion in the micrometer to nanometer range. The advantages of a broader range of motion, rapid response, higher stiffness, and large actuation force from piezoelectric actuators make them suitable for precision positioning applications. However, the inherent nonlinearity in the piezoelectric actuators under dynamic working conditions severely affects the accuracy of the generated motion. The nonlinearity in the piezoelectric actuators arises from hysteresis, creep, and vibration, which affect the performance of the piezoelectric actuator. Thus, there is a need for appropriate modeling and control approaches for piezoelectric actuators, which can model the nonlinearity phenomenon and provide adequate compensation to achieve higher motion accuracy. The present review covers different methods adopted for overcoming the nonlinearity issues in piezoelectric actuators. This review highlights the charge-based and voltage-based control methods that drive the piezoelectric actuators. The survey also includes different modeling approaches for the creep and hysteresis phenomenon of the piezoelectric actuators. In addition, the present review also highlights different control strategies and their applications in various types of piezoelectric actuators. An attempt is also made to compare the piezoelectric actuator’s different modeling and control approaches and highlight prospects. © 2023 by the authors. Licensee MDPI, Basel, Switzerland.Item A study and implementation of mapping and speech recognition techniques for an autonomous mobile robot based on ROS(Inderscience Enterprises Ltd., 2017) Srinivasa Rao, H.; Desai, V.; Bhat, R.; Jayaprakash, S.; Sampangi, Y.Autonomous mobile robots work in close interaction with humans in environments such as homes, hospitals, public places and disaster areas. In autonomous mobile robots, the main constraints are safety, autonomy and efficiency in helping the humans. Given these constraints, developing the autonomous mobile robot technologies is a major challenge for both the industry and the research society. This paper work is about how an indoor autonomous mobile robot can work based on robot operating system and using Lidar and other sensors to create a map of an environment, and perform autonomous navigation with using capabilities like dynamic obstacle avoidance, speech recognition and video streaming. To achieve the above features, different algorithms like SLAM, AMCL, dynamic window approach algorithms, and CMU PocketSphinx speech recogniser are used. For video steaming, ROS web video server is used and the recorded video can be sent to a remote desktop system using ROS network. © 2017 Inderscience Enterprises Ltd.Item Microstructure and mechanical properties of austempered AISI 9255 high-silicon steel(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Acharya, P.P.; Udupa, R.; Bhat, R.The present investigation is focused on evaluating the microstructure and mechanical properties of American Iron and Steel Institute 9255 high-silicon steel austempered at different temperatures and durations. Material characterisation was done using a scanning electron microscope and an X-ray diffractometer. Results show the bainite microstructure over a temperature range of 280–400°C. Bainite structure gains coarseness at higher temperatures at 360 and 400°C. A significant improvement in the tensile properties was observed for all austempered specimens; with a maximum tensile strength of 1852 MPa and elongation up to 35%. An excellent strain hardening response was observed from the samples austempered at temperatures of 360 and 400°C. Tensile properties were found to be superior at 15 min of austempering duration for all austempering temperatures. © 2017 Institute of Materials, Minerals and Mining.Item Fabrication of Zn-Ni alloy coatings from acid chloride bath and its corrosion performance(Center of Excellence in Electrochemistry, Univ. of Tehran ganjali@abechem.com, 2018) Bhat, R.; Bekal, S.; Hegde, A.Optimization of acidic chloride bath containing triethanolamine and citric acid for deposition of a smooth and uniform Zn-Ni alloy coating over mild steel is discussed in the present work. Bath constituents and operating parameters were optimized by standard Hull cell method. Triethanolamine and citric acid were used as additives altered the phase content in the coatings, most likely as a result of their adsorption at the surface of the cathode. The effect of citric acid was more pronounced than that of triethanolamine. The composition of coatings was determined by using colorimetric method. The bath followed anomalous codeposition with preferential deposition of Zn over nobler metal Ni. The experimental results reveal that a bright Zn-Ni alloy coating having ~4.92 wt.%Ni was showing peak performance of the coating against corrosion. Deposition was carried out under different condition of current densities and molar ratio of [Ni +2 ]/[Zn +2 ]. No transition current densities at which codeposition behaviour changed from anomalous to normal type was observed. The cathode current efficiency was higher than 80%. As the current density was increased or the bath temperature was decreased, the concentration of the nobler metal in the coating was increased. The thickness and hardness of all coatings increased as the applied current density was increased. The throwing power and reflectance of the coating was increased with current density to a peak value, and then decreased. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were used to assess the corrosion resistance of Zn-Ni alloy coatings at different current densities. Surface morphology of the coatings was examined using Scanning Electron Microscopy (SEM). A new and cheap Chloride bath, for bright Zn–Ni alloy coating on mild steel has been proposed, and results are discussed. © 2018 by CEE (Center of Excellence in Electrochemistry).Item Predictive analysis of peel up delamination in glass fibre reinforced polyester composite drilling(Transstellar Journal Publications and Research Consultancy Private Limited (TJPRC) editor@tjprc.org, 2019) Bhat, R.; Mohan, N.; Kulkarni, S.M.; Sharma, S.Composites are the engineering materials, comprising two constituents: reinforcing and the matrix or binder material. the composite machining, particularly, drilling is a complex process in comparison to the machining of traditionally employed engineering structural materials. Delamination is the most prevalent integrity issue in composite drilling. In the present work, the independent variables are categorized as continuous and categorical variables. Speed and feed are chosen as the continuous variables, whereas, the drill tool diameter and material thickness are considered as categorical variables. The peel up delamination is chosen as the response. The central composite design form of RSM is employed to develop the experimental design and develop the response regression model. The developed model is then validated using an additional set of small number of experiments and the degree of affirmation is determined. The standard error obtained analytically is 5.91%. The experimental mean standard error for the randomly conducted validating experiment obtained is 4.23%. The validation shows a high degree of agreement (99.75%) between the theoretical and analytical values. © TJPRC Pvt. Ltd.Item Studies on electrodeposited Zn-Fe alloy coating on mild steel and its characterization(International Association of Physical Chemists zmandic@fkit.hr, 2019) Bhat, R.; Hegde, A.C.Chloride bath containing ZnCl2.7H2O, FeCl2.H2O and a combination of sulphamic acid and citric acid (SA+CA) were optimized for electrodeposition of bright Zn-Fe alloy coating on the mild steel. Bath constituents and operating parameters were optimized by the Hull cell method for highest performance of the coating against corrosion. The effect of current density and temperature on deposit characteristics such as corrosion resistance, hardness, thickness, cathode current efficiency and glossiness, were studied. Potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) methods were used to assess corrosion behaviour. Surface morphology of coatings was examined using scanning electron microscopy (SEM). The Zn-Fe alloy with intense peaks corresponding to Zn (100) and Zn (101) phases, evidenced by X-ray diffraction (XRD) study, showed the highest corrosion resistance. A new and economical chloride bath for electrodeposition of bright Zn-Fe alloy coating on mild steel was proposed and discussed. © 2019 by the authors.Item Structure-Property Correlation of Quenching and Partitioning Heat Treated Silicon-Manganese Steel(Springer Netherlands rbk@louisiana.edu, 2019) Acharya, P.P.; Bhat, R.The present investigation deals with the effect of varying quenching and partitioning parameters on microstructure and mechanical properties of American Iron and Steel Institute 9255 steel. The specimens were fully austenitised at 900 ?C for 45 min and then quenched at 190 ?C and followed by partitioning at various temperatures 280, 320, 360 and 400 ?C and partitioning times 15, 30, 45, 60 and 90 min for each temperature. Post heat treatment includes microstructural analysis that was carried out by using scanning electron microscope (SEM) along with electron back scattered diffraction (EBSD) and x-ray diffraction (XRD) and then correlated to the mechanical properties i.e. tensile properties and hardness of the steel. Results indicate that the specimens quenched at 190 ?C and partitioned over a temperature range 280 to 400 ?C generates multiphase microstructures containing major fraction of martensitic structure (lath and plate-type), transitional ?-carbides in tempered martensite matrix and retained austenite (RA) for all the conditions. At higher partitioning temperatures i.e. 360 and 400 ?C reveals some bainitic ferrite laths along with martensite and RA. Superior tensile strength, % elongation and modulus of toughness values of 1860 MPa, 12% and 207 MJ/m3 respectively was attained at partitioning time of 15 min at 280 ?C. © 2018, Springer Nature B.V.Item Dynamic force modelling and experimental analysis of reaming(Engineered Science Publisher, 2021) Kamath, C.R.; Bekinal, S.I.; Bhat, R.; Naik, N.; Kuttan, A.The production Reaming process plays a vital role in several applications, ranging from automotive to medical sectors. It is performed to enlarge the pre-drilled hole to obtain its required diameter within the specified tolerance limits. The typical operational faults found in the reaming process significantly contribute to damage in the final hole quality. Thus, a dynamic force model is developed in the present work to predict the cutting forces developed during the reaming process. The inputs to the model are broadly classified into tool geometry and vibration system elements. The cutting forces acting in all three directions during the reaming are predicted. The double modulation principle is applied to develop the dynamic force model for computing the cutting forces in the reaming process. The dynamic force model thus developed and simulated using MATLAB® R2019b is examined and validated through actual experiments for no fault conditions. The results obtained infer a high degree of fitness between the values obtained from the developed mechanistic model and the experimental values with a prediction error of less than 5%. © 1999. The American Astronomical Society. All rights reserved.Item Design and Optimization of Multi-ring Permanent Magnet Bearings for High-speed Rotors - A Computational Framework(Engineered Science Publisher, 2021) Kamath, C.R.; Bhat, R.; Bekinal, S.I.; Vijay, G.S.; Shetty, T.S.; Doddamani, M.This article presents a computational framework (MATLAB app) suitable for the industrial use for selecting optimum multi-ring radial and thrust permanent magnet bearings (PMB) based on two general variables (outer diameter/air gap and length of a bearing). Such an approach eliminates the usage of complex design equations and optimization methods. The detailed methodology adopted in optimizing PMB for maximum characteristics is presented with mathematical equations of force and stiffness. Then, the steps involved in the development of the computational framework are discussed in depth. Further, usage of the computational framework is explained with examples of PMB, and results obtained are validated with the mathematical model results. Regarding the mathematical model results, deviations of 2.22 % and 1.78 % are observed among the maximized radial and axial force values in the app results. Finally, the effectiveness of the proposed framework is demonstrated by discussing the case studies from the literature. © Engineered Science Publisher LLC 2021.Item An Optimization Study on Material Selection for FRPCs in Multi Layered Armour System through Hybrid MCDM Approach and Numerical Simulation(Syscom 18 SRL, 2022) Gowda, D.; Bhat, R.; Rajole, S.Fiber reinforced polymer composites (FRPCs) are considered as core structure in Multi layered armour systems (MAS) to take advantage of maximum energy absorption, mobility and cost criteria design. In this article, based on the problem defining attribute’s optimal material selection in FRPCs determined by Multiple criteria decisions making (MCDM) approach for considered alternative materials from polymer resin, synthetic and natural fiber. Attribute’s weightage and alternatives priority rank were determined through Fussy-Analytical hierarchy process (F-AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. Obtained rank was compared with Preference selection index (PSI) an another MCDM method, for better computational conformity. Selected materials from MCDM approach, simulated for energy absorption ability and damage after impact were studied by considering Cowper-Symonds constitutive materials model using 3D macro shell analysis. Various impact velocities were considered from 3 to 50 m/s for rigid steel impactor directed towards the deformable plate. Parameter like Residual kinetic energy, Residual velocity, Energy absorption ratio after impact were studied numerically. Simulation results in terms of specific energy absorption were compared with the rank obtained in MCDM approach. Among the polymers considered epoxy, polyurethane and polyester found better choice. In fibers hemp and basalt found better materials choice for heterogenous FRPCs design in ballistic armour. © 2022 Syscom 18 SRL. All rights reserved.