Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Author: search.filters.author.Rao, S.S.Subject: search.filters.subject.Surface roughness

Search Results

Now showing 1 - 10 of 23
  • No Thumbnail Available
    Item
    Comparison of Response Surface Methodology (RSM) and Machine Learning Algorithms in Predicting Tensile Strength and Surface Roughness of AA8090/B4C Surface Composites Fabricated by Friction Stir Processing
    (Springer Science and Business Media Deutschland GmbH, 2024) Adiga, K.; Herbert, M.A.; Rao, S.S.; Shettigar, A.K.; Shrivathsa, T.V.; Tapariya, R.
    Friction stir processing is an innovative solid-state process, widely utilized for surface composite fabrication, material property enhancement, and microstructural modification. Rotational speed, traverse speed, groove width, and axial force are key FSP parameters that improve the characteristics of surface composites (SCs). This work makes use of FSP to fabricate AA8090/B4C SCs by altering parameters within ranges. Response variables include ultimate tensile strength (UTS) and surface roughness (SR). Central composite design (CCD) of response surface methodology (RSM) leads trials, establishing a mathematical relationship between input parameters and UTS/SR. The models’ adequacy is validated using ANOVA, which investigates the impact of input parameters on UTS and SR. This study also looks into machine learning regression methodologies for UTS and SR forecasting in AA8090/B4C SCs. The ML algorithms are evaluated by utilizing performance metrics like coefficient of determination (R2) and root mean squared error (RMSE). Predicted UTS and SR values from RSM are compared with machine learning outcomes. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
  • No Thumbnail Available
    Item
    Steam as coolant and lubricant in turning of metal matrix composites
    (2008) Shetty, R.; Pai B, R.B.; Kamath, V.; Rao, S.S.
    Green cutting has become focus of attention in ecological and environmental protection. Steam is cheap, pollution-free and eco-friendly, and then is a good and economical coolant and lubricant. Steam generator and steam feeding system were developed to generate and feed steam. Comparative experiments were carried out in cutting AA6061-15 vol.% SiC (25 ?m particle size), with cubic boron nitride (CBN) insert KB-90 grade under the conditions of compressed air, oil water emulsion, steam as coolant and lubricant, and dry cutting, respectively. The experimental results show that, with steam as coolant and lubricant, gradual reduction in the cutting force, friction coefficient, surface roughness and cutting temperature values were observed. Further, there was reduction in built up edge formation. It is proved that use of water steam as coolant and lubricant is environmentally friendly. © 2008 Zhejiang University and Springer-Verlag GmbH.
  • No Thumbnail Available
    Item
    Taguchi's technique in machining of metal matrix composites
    (Brazilian Society of Mechanical Sciences and Engineering, 2009) Shetty, R.; Pai B, R.B.; Rao, S.S.; Nayak, R.
    This paper presents the study on Taguchi's optimization methodology, which is applied to optimize cutting parameters in turning of age hardened Al6061-15% vol. SiC 25 ?m particle size metal matrix composites with Cubic boron nitride inserts (CBN) KB-90 grade using steam as cutting fluid. Analysis of variance (ANOVA) is used to study the effect of process parameters on the machining process. This procedure eliminates the need for repeated experiments, time and conserves the material by the conventional procedure. The turning parameters evaluated are speed, feed, depth of cut, nozzle diameter and steam pressure. A series of experiments are conducted using PSG A141 lathe (2.2 KW) to relate the cutting parameters on surface roughness, tool wear, cutting force, feed force, and thrust force. The measured results were collected and analyzed with the help of the commercial software package MINITAB15. As well, an orthogonal array, signal-to-noise ratio is employed to analyze the influence of these parameters. The method could be useful in predicting surface roughness, tool wear, cutting force, feed force and thrust force as a function of cutting parameters. From the analysis using Taguchi's method, results indicate that among the all-significant parameters, steam pressure is the most significant parameter. © 2009 by ABCM.
  • No Thumbnail Available
    Item
    Development of a surface roughness prediction system for machining of hot chromium steel (AISI H11) based on artificial neural network
    (Medwell Journals medwellonline@gmail.com, 2010) Rai, R.; Shettigar, A.; Rao, S.S.; Shriram
    An attempt have been made to apply the principles of artificial neural networks (ANN) towards developing a prediction model for surface roughness during the machining of high chromium steel through face milling process. Now a days, hot chromium steel is prominently used in die and mould industry as well as in press tools, helicopter rotor blades, etc. Initially, Taguchi design of experiments was applied while conducting the experiments to reduce the time and cost of experiment. Multilayer perceptron (MLP) network using Feed Forward Error Back propagation was chosen as the neural network architecture to describe the process model. The experiments were conducted on a C.N.C milling machine using carbide cutters. Pearson correlation coefficient was also calculated to analyze the correlation between the system inputs and selected system output i.e. surface roughness. The results of ANN modeling were substantiated by testing and validation of the resulting surface roughness values and the results have been encouraging. The outputs of Pearson correlation coefficient also showed a strong correlation between the feed per tooth and surface roughness, followed by cutting speed. © 2006-2010 Asian Research Publishing Network (ARPN).
  • No Thumbnail Available
    Item
    Application of response surface methodology on surface roughness in grinding of aerospace materials (6061Al-15Vol%SiC25P)
    (2010) Dayananda Pai, D.; Rao, S.S.; Shetty, R.; Nayak, R.
    In this paper, the effects and the optimization of machining parameters on surface roughness in the grinding of 6061Al-SiC25P (MMCs) specimen are investigated. In the grinding process, a machining parameter, such as hardness of the specimen, flow rate of the coolant and depth of cut while machining were chosen for evaluation by the response surface methodology. By response surface methodology, a complete realization of the process parameters and their effects were achieved. The variation of surface roughness with machining parameters was mathematically modeled using response surface methodology. Finally, experimentation was carried out to identify the effectiveness of the proposed method. © 2006-2010 Asian Research Publishing Network (ARPN). All rights reserved.
  • No Thumbnail Available
    Item
    Role of surface roughness in pool boiling with Alumina-water nanofluid on a horizontal wire surface
    (International Information and Engineering Technology Association, 2011) Hegde, R.N.; Rao, S.S.; Reddy, R.P.
    Boiling heat transfer is one of the major phenomenon which of late, has drawn the attention of many researchers and scientists throughout the world. With nanofluids, further boost is given in heat transfer enhancement. This research paper is the study of heat transfer enhancement using Alumina nanofluid in different volume concentrations ranging from 1 to 9%. The role of surface roughness on critical heat flux enhancement (CHF) in pool boiling with nanofluids was experimentally studied using a 36 gauge NiCr wire at atmospheric pressure. Experimentation included i) investigations on boiling heat transfer subjecting the wire surface to Alumina nanofluid at higher volume concentrations and ii) investigations on surface roughness due to surface coating, subjecting the wire surface to a single heating cycle with different volume concentrations of Alumina nanofluid. Boiling of nanofluid resulted in nanoparticle deposition and subsequent roughning of the wire surface. To substantiate the nanoparticle deposition and its effect on critical heat flux, investigation was done by studying the surface roughness and SEM images of the wire surface. The experimental results show the evidence of nanoparticle deposition on the wire surface and its effect on CHF enhancement and deterioration in pool boiling heat transfer.
  • No Thumbnail Available
    Item
    Behavioral study of alumina nanoparticles in pool boiling heat transfer on a vertical surface
    (2011) Hegde, R.N.; Reddy, R.P.; Rao, S.S.
    Experiments were carried out to investigate the pool boiling of alumina-water nanofluid at 0.1 g/l to 0.5 g/l of distilled water, and the nucleate pool boiling heat transfer of pure water and nanofluid at different mass concentrations were compared at and above the atmospheric pressure. At atmospheric pressure, different concentrations of nanofluids display different degrees of deterioration in boiling heat transfer. The effect of pressure and concentration of nanoparticles revealed significant enhancement in heat flux and deterioration in pool boiling. The heat transfer coefficient of 0.5 g/l alumina-water nanofluid was compared with pure water and clearly indicates deterioration. At all pressures the heat transfer coefficients of the nanofluid were lower than those of pure water. Experimental observation revealed particles coating over the heater surface and subsequent SEM inspection of the heater surface showed nanoparticles coating on the surface forming a porous layer. To substantiate the nanoparticle deposition and its effect on heat flux, investigation was done by measuring the surface roughness of the heater surface before and after the experiment. While SEM images of the heater surface revealed nanoparticle deposition, surface roughness of the heater surface confirmed it. Based on the experimental investigations it can be concluded that an optimum thickness of nanoparticles coating favors an increase in heat flux. Higher surface temperature due to the presence of nanoparticles coating results in the deterioration of boiling heat transfer. © 2011 Wiley Periodicals, Inc.
  • No Thumbnail Available
    Item
    Experimental study on CuO nanoparticles in distilled water and its effect on heat transfer on a vertical surface
    (2011) Hegde, R.N.; Rao, S.S.; Reddy, R.P.
    The pool boiling characteristics of dilute dispersions of CuO nanoparticles in water were studied at atmospheric pressure on a vertical heating surface. Experimental investigation of different weight concentrations of nanoparticles revealed significant enhancement in heat flux and deterioration in pool boiling. Out of many reasons, nanoparticles coating the heater surface was believed to be the reason behind this. Subsequent inspection of the heater surface showed nanoparticles coating the surface, forming a porous layer. To substantiate the nanoparticle deposition and its effect on heat flux, an investigation was performed by measuring the surface roughness of the heater surface before and after the experiment. While SEM images of the heater surface revealed nanoparticle deposition, measurement of surface roughness of the heater surface confirmed it. Formation of the porous layer on the heater surface as revealed by SEM images provided an excellent location for nucleation sites enhancing heat transfer. However, deterioration in nucleate boiling at different weight concentrations indicated some phenomenon is working behind this. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.
  • No Thumbnail Available
    Item
    Flow visualization and study of critical heat flux enhancement in pool boiling with Al2O3-water nanofluids
    (Serbian Society of Heat Transfer Engineers, 2012) Hegde, R.N.; Rao, S.S.; Reddy, R.P.
    Pool boiling heat transfer characteristics of Al2O3 -water nanofluids is studied experimentally using a NiCr test wire of 36 standard wire guage diameter. The experimental work mainly concentrated on (1) change of critical heat flux with different volume concentrations of nanofluid and (2) flow visualization of pool boiling using a fixed concentration of nanofluid at different heat flux values. The experimental work revealed an increase in critical heat flux value of around 48% andflow visualization helped in studying the pool boiling behaviour of nanofluid.Out of the various reasons which could affect the critical heatflux enhancement, surface roughness plays a major role in pool boiling heat transfer.
  • No Thumbnail Available
    Item
    Studies on nanoparticle coating due to boiling induced precipitation and its effect on heat transfer enhancement on a vertical cylindrical surface
    (2012) Hegde, R.N.; Rao, S.S.; Reddy, R.P.
    Pool boiling experiments were conducted to study the heat transfer characteristics using low concentrations (0.1-0.5. g/l) of Alumina-nanofluid at atmospheric pressure in distilled water. The study involved investigation on the effect of nanoparticle coating on the vertical test surface exposed to multiple heating cycles, heat transfer characteristics of nanoparticle coated surface in distilled water and pool boiling behavior of Alumina nanofluid subjected to transient characteristics. In order to quantify the result, surface roughness of the cylindrical surface was measured at different concentrations of nanofluid before and after the experiments. At atmospheric pressure, different concentrations of nanofluids displayed different degrees of deterioration in boiling heat transfer. Coating of nanoparticles was observed on the heater surface due to boiling induced precipitation. The nanoparticle coated heater when tested in pure water showed significant increase in CHF comparable to CHF of bare heater tested in pure water. Study on transient characteristics of the nanofluid, keeping the heat flux constant for a specified time interval showed degradation in boiling heat transfer. The longer the duration of exposure of the heater surface, the higher was the degradation in heat transfer. Based on the experimental investigations it can be concluded that nanoparticle coating can be a potential substitute for enhancing the heat transfer. © 2011 Elsevier Inc.