Browsing by Author "Herbert, M."

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    Application of neural network for the prediction of tensile properties of friction stir welded composites
    (2017) Shettigar, A.K.; Prabhu, S.; Malghan, R.; Rao, S.; Herbert, M.
    In this paper, an attempt has been made to apply the neural network (NN) techniques to predict the mechanical properties of friction stir welded composite materials. Nowadays, friction stri welding of composites are predominatally used in aerospace, automobile and shipbuilding applications. The welding process parameters like rotational speed, welding speed, tool pin profile and type of material play a foremost role in determining the weld strength of the base material. An error back propagation algorithm based model is developed to map the input and output relation of friction stir welded composite material. The proposed model is able to predict the joint strength with minimum error. � 2017 Trans Tech Publications, Switzerland.
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    Application of neural network for the prediction of tensile properties of friction stir welded composites
    (Trans Tech Publications Ltd ttp@transtec.ch, 2017) Shettigar, A.K.; Prabhu B, S.; Malghan, R.; Rao, S.S.; Herbert, M.
    In this paper, an attempt has been made to apply the neural network (NN) techniques to predict the mechanical properties of friction stir welded composite materials. Nowadays, friction stri welding of composites are predominatally used in aerospace, automobile and shipbuilding applications. The welding process parameters like rotational speed, welding speed, tool pin profile and type of material play a foremost role in determining the weld strength of the base material. An error back propagation algorithm based model is developed to map the input and output relation of friction stir welded composite material. The proposed model is able to predict the joint strength with minimum error. © 2017 Trans Tech Publications, Switzerland.
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    Effect of low temperature annealing on the wear properties of NITINOL
    (Institute of Physics Publishing michael.roberts@iop.org, 2016) Mukunda, S.; Naths, N.; Herbert, M.; Mukunda, P.G.
    NiTi shape memory alloy is a wonder material that is a solution looking for problems. The material finds wide biomedical applications like endodontic files for root canal treatment and cardiovascular stents. This material has rendered the surgical procedure simple compared to that with the existing Stainless Steel (SS) or titanium ones. NiTi as an endodontic file would cause less discomfort to the patients in comparison to that with far stiffer SS or titanium ones. Here nearly equi-atomic 50:50 commercial NiTi rods were subjected to low temperature aging at 300 to 450°C. The wear resistance of the as-received and the heat-treated samples was studied using adhesive wear tests on hardened steel counter face. Abrasive wear tests were run against Alumina disc to simulate the working of endodontic drills and files against dental hard and soft tissues. The abrasive wear resistance is expected to be proportional to the Vickers Hardness of the material and is high for the 450°C heat-treated sample. A correlation between the mechanical properties and microstructures of this material is attempted. © Published under licence by IOP Publishing Ltd.
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    Influence of welding process parameters on microstructure and mechanical properties of friction stir welded aluminium matrix composite
    (2017) Prabhu, S.; Shettigar, A.K.; Rao, K.; Rao, 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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    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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    Investigation on microstructure and mechanical properties of Friction Stir Welded AA6061-4.5Cu-10SiC composite
    (Institute of Physics Publishing michael.roberts@iop.org, 2016) Herbert, M.; Shettigar, A.K.; Nigalye, A.V.; Rao, S.S.
    The application of Metal Matrix Composites (MMCs) is restricted by the availability of properly developed fabrication methods. The main challenge here is the fabrication and welding of MMCs in a cost effective way. In the present study, synthesis of AA6061-4.5%Cu- 10%SiC composite was done by stir casting method. The joining of MMCs was performed by Friction Stir Welding (FSW) using a combination of square and threaded profile pin tool (CSTPP). Further, the welded composite was evaluated for microstructure and joint properties. The microstructural characterization showed uniform distribution of refined fine grains and numerous small particles at nugget zone. The hardness at the stir zone is higher than that of the base material. The tensile test revealed 96% joint efficiency in transverse direction. © Published under licence by IOP Publishing Ltd.
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    Machining Parameters Optimization of AA6061 Using Response Surface Methodology and Particle Swarm Optimization
    (SpringerOpen, 2018) Lmalghan, R.; Karthik, K.; Shettigar, A.; Rao, S.; Herbert, M.
    The influence of cutting parameters on the responses in face milling has been examined. Spindle speed, feed rate and depth of cut have been considered as the influential factors. In accordance with the design of experiments (DOE) a series of experiments have been carried out. The paper exemplifies on the optimizing the process parameters in milling through the application of Response surface methodology (RSM), RSM-based Particle Swarm Optimization (PSO) technique and Desirability approach. These aforesaid techniques have been applied to experimentally establish data of AA6061 aluminium material to study the effect of process parameters on the responses such as cutting force, surface roughness and power consumption. By adopting the multiple regression techniques, the interaction between the process parameters are acquired. The optimal parameters have been found by adopting the multi-response optimization techniques, i.e. desirability approach and PSO. The performance capability of PSO and desirability approach is investigated and found that the values obtained from PSO are comparable with the values of desirability approach. © 2018, Korean Society for Precision Engineering and Springer-Verlag GmbH Germany, part of Springer Nature.
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    Multi Response Optimization of Friction Stir Welding Process Variables using TOPSIS approach
    (2018) Prabhu, S.R.; Shettigar, A.; Herbert, M.; Rao, S.
    Being a solid state welding process, the friction stir welding (FSW) is extensively used these days, to join difficulty-to-weld materials such as aluminium alloys and its composites. This study emphasizes on friction stir welding of aluminium matrix composite (AMC) reinforced with silicon carbide particle. The FSW tool geometry and process variables play a vital role in governing the joint strength. Size of the grain and the hardness at the weld region influences the joint strength. Process variables such as tool revolving speed, tool traverse speed and the tool pin profile are optimized with multiple responses such as % elongation, tensile strength and hardness. In the present study a technique for order preference by similarity to ideal solution (TOPSIS) approach is used to solve multiple response optimization problems. The optimal solution reveals that the multiple response characteristics of the FS welded AMCs can be improved through the TOPSIS approach. � Published under licence by IOP Publishing Ltd.
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    Multi Response Optimization of Friction Stir Welding Process Variables using TOPSIS approach
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Prabhu B, S.R.; Shettigar, A.; Herbert, M.; Rao, S.
    Being a solid state welding process, the friction stir welding (FSW) is extensively used these days, to join difficulty-to-weld materials such as aluminium alloys and its composites. This study emphasizes on friction stir welding of aluminium matrix composite (AMC) reinforced with silicon carbide particle. The FSW tool geometry and process variables play a vital role in governing the joint strength. Size of the grain and the hardness at the weld region influences the joint strength. Process variables such as tool revolving speed, tool traverse speed and the tool pin profile are optimized with multiple responses such as % elongation, tensile strength and hardness. In the present study a technique for order preference by similarity to ideal solution (TOPSIS) approach is used to solve multiple response optimization problems. The optimal solution reveals that the multiple response characteristics of the FS welded AMCs can be improved through the TOPSIS approach. © Published under licence by IOP Publishing Ltd.
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    Population Based Metaheuristic Algorithm Approach for Analysis of Multi-Item Multi-Period Procurement Lot Sizing Problem
    (Hindawi Limited 410 Park Avenue, 15th Floor, 287 pmb New York NY 10022, 2017) Kumar, P.; Herbert, M.; Rao, S.
    This research study focuses on the optimization of multi-item multi-period procurement lot sizing problem for inventory management. Mathematical model is developed which considers different practical constraints like storage space and budget. The aim is to find optimum order quantities of the product so that total cost of inventory is minimized. The NP-hard mathematical model is solved by adopting a novel ant colony optimization approach. Due to lack of benchmark method specified in the literature to assess the performance of the above approach, another metaheuristic based program of genetic algorithm is also employed to solve the problem. The parameters of genetic algorithm model are calibrated using Taguchi method of experiments. The performance of both algorithms is compared using ANOVA analysis with the real time data collected from a valve manufacturing company. It is verified that two methods have not shown any significant difference as far as objective function value is considered. But genetic algorithm is far better than the ACO method when compared on the basis of CPU execution time. © 2017 Prasanna Kumar et al.