Faculty Publications

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    Influence of welding process parameters on microstructure and mechanical properties of friction stir welded aluminium matrix composite
    (Trans Tech Publications Ltd ttp@transtec.ch, 2017) Prabhu B, S.; Shettigar, A.K.; Karthik, K.; Rao, S.S.; Herbert, M.
    In this study, the effect of process parameters on microstructure and mechanical properties of friction stir welded aluminium matrix composites(AMC) have been explored. The results indicated that the recrystallized grain size at the bottom of the weld region is smaller than that at the top region due to difference in the heat transfer at the weld region. The joint strength of AMCs depends on proper selection of process parameters like tool rotational speed and welding speed. If process parameter values are beyond the optimal value, the joint strength decreases due to formation of defects. Maximum tensile strength is obtained for rotational speed of 1000 rpm and welding speed of 80mm/min. © 2017 Trans Tech Publications, Switzerland.
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    Application of particle swarm optimization and response surface methodology for machining parameters optimization of aluminium matrix composites in milling operation
    (Springer Verlag service@springer.de, 2017) Malghan, R.L.; Karthik, K.M.C.; Shettigar, A.K.; Rao, S.S.; D’Souza, R.J.
    Face milling is extensively used machining operation to generate the various components. Usually the selection of the process parameters are incorporated by trial and error method, literature survey and the machining hand book. This kind of selection of process parameters turns out to be very tedious and time-consuming. In order to overcome this there is a need to develop a technique that could be able to find the optimal process parameters for the desired responses in machining. The present paper illustrates an application of response surface methodology (RSM) and particle swarm optimization (PSO) technique for optimizing the process parameters of milling and provides a comparison study among desirability and PSO techniques. The experimental investigations are carried out on metal matrix composite material AA6061-4.5%Cu-5%SiCp to study the effect of process parameters such as feed rate, spindle speed and depth of cut on the cutting force, surface roughness and power consumption. The process parameters are analyzed using RSM central composite face-centered design to study the relationship between the input and output responses. The interaction between the process parameters was identified using the multiple regression technique, which showed that spindle speed has major contribution on all the responses followed by feed rate and depth of cut. It has shown good prediction for all the responses. The optimized process parameters are acquired through multi-response optimization using the desirability approach and the PSO technique. The results obtained from PSO are closer to the values of the desirability function approach and achieved significant improvement. © 2016, The Brazilian Society of Mechanical Sciences and Engineering.
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    Microstructure evolution and mechanical properties of friction stir welded AA6061/rutile composite
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Prabhu B, S.R.; Shettigar, A.K.; Herbert, M.A.; Rao, S.S.
    Present study explores the Friction stir welding (FSW) of rutile reinforced AA6061matrix composite using various combination of tool traverse speeds (60, 75 and 90 mm min-1), rotational speeds (750, 1000 and 1250 rpm) and tool pin profiles (Threaded cylindrical and Square profiled pin). FSW process variables have significant impact in controlling the mechanical properties of the joint by limiting the welding defects. It has been inferred from the study that tool rotational speed and tool traverse speed majorly affects the microstructure, joint quality, hardness and joint strength. The weld area showed the presence of four distinct regions usually found in FSW of aluminium matrix composites. The weld region exhibited fine equiaxed grains and uniformly distributed tiny reinforced rutile particles. Tool having square profiled pin shows improved joint properties in comparison with tool having threaded cylindrical pin. © 2019 IOP Publishing Ltd.
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    Microstructure and mechanical properties of rutile-reinforced AA6061 matrix composites produced via stir casting process
    (Nonferrous Metals Society of China B12 Fuxing Road Beijing 100814, 2019) Prabhu B, S.R.; Shettigar, A.K.; Herbert, M.A.; Rao, S.S.
    A novel process of fabricating aluminium matrix composites (AMCs) with requisite properties by dispersing rutile particles in the aluminum matrix was studied. A novel bi-stage stir casting method was employed to prepare composites, by varying the mass fractions of the rutile particles as 1%, 2%, 3% and 4% in AA6061 matrix. The density, tensile strength, hardness and microstructures of composites were investigated. Bi-stage stir casting method engendered AMCs with uniform distribution of the reinforced rutile particles in the AA6061 matrix. This was confirmed by the enhancement of the properties of AMCs over the parent base material. Rutile-reinforced AMCs exhibited higher tensile strength and hardness as compared with unreinforced parent material. The properties of the composites were enhanced with the increase in the mass fraction of the rutile particles. However, beyond 3 wt.% of rutile particles, the tensile strength decreased. The hardness and tensile strength of the AMCs reinforced with 3 wt.% of rutile were improved by 36% and 14% respectively in comparison with those of matrix alone. © 2019 The Nonferrous Metals Society of China
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    Optimization of FSW process parameters for maximum UTS of AA6061/rutile composites using Taguchi technique
    (Sharif University of Technology, 2022) Prabhu B, S.R.; Shettigar, A.; Herbert, M.A.; Rao, S.S.
    In the friction stir welding process, preferred joint property is vastly reliant on the selection of optimal welding conditions. The present study aims to use the Taguchi technique to find the optimal process conditions for achieving superior Ultimate Tensile Strength (UTS) in friction stir welded Aluminum Matrix Composite (AMC) joints. AMCs reinforced with rutile particles which have a potential application in the aerospace, automotive, and marine industries are used in the present work. Taguchi parametric design technique was used to identify the effect of rotational speed, tool traverse speed, and tool geometry on joint strength. Taguchi approach confined the optimum level of process variables and these variables were optimized. The investigation showed that the parameters within the selected value range will seriously affect the output. The predicted value of the output response was 155.48 MPa, which was validated by further experiments using the optimum process variables. Analysis Of Variance (ANOVA) results indicated that the UTS of the composite joint is mainly affected by the tool traverse speed followed by rotational speed, and tool geometry. The microstructural study unveiled that grain size is dependent on process variables and finer grains offer better joint properties. © 2022 Sharif University of Technology. All rights reserved.