Faculty Publications

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Publications by NITK Faculty

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Now showing 1 - 10 of 24
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    Fly ash-reinforced poly(vinyl alcohol) composites
    (Elsevier, 2021) Anandhan, S.; SelvaKumar, S.; Patil, A.G.
    Fly ash (FA) is a waste residue and huge amounts of it have been produced from coal-fired power plants. As a result, it has become a serious issue and there is an urgent need to reduce its accretion as well as improve the safe disposal of FA as it has many toxic constituents including lead, arsenic, and chromium. In an effort to utilize FA, it has been widely used as filler for fabricating polymer composites to improve their performance. Recently, FA-incorporated polymers have received the attention of researchers and industries due to their remarkable properties, such as improved mechanical strength without sacrificing their elasticity, thermal, flame resistance, wettability, resistance to hydrolysis, and possessing excellent dynamic mechanical properties even at low temperatures. In comparison with conventional FA-based polymer composites, those based on surface-modified FA and nanostructured FA (NFA) exhibit superior mechanical and technical properties. The present article reviews various aspects of poly(vinyl alcohol)/FA-based composites. It also focuses on the effect of particle size reduction of FA on the physicochemical properties of poly(vinyl alcohol)/NFA composites. © 2022 Elsevier Inc. All rights reserved.
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    Thermal properties of maize fiber reinforced unsaturated polyester resin composites
    (2013) Saravana Bavan, B.D.; Mohan, K.G.C.
    Increase in demand for natural fiber composites are raising today because of more advantage when compared to traditional fiber composites. In the present work, natural fiber composite material is processed by vacuum assisted resin transfer molding technique and the fibers are maize stalk fibers with matrix of unsaturated polyester resin. With suitable catalyst and accelerator composite material is fabricated and thermal properties for the material is examined by thermal gravimetric analyzer, differential scanning calorimeter and the results are also compared with finite element method.
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    Effect of FSW on microstructure and hardness of AA6061/SiC/fly ash MMCs
    (Elsevier Ltd, 2018) Patil, S.; Narendranath, S.; Dupadu, D.
    In this study 6 mm thick plates of aluminum matrix composites (AMCs) composed of AA6061/SiC (10 Wt. %) /fly ash (7.5 Wt. %) were butt welded using friction stir welding (FSW. Microstructural characterization of weld joints was conducted by using optical microscopy (OM) and scanning electron microscopy (SEM). The microstructure of the weld revealed the presence of four different zones like nugget zone (NZ), thermo mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM). Nugget zone reveals homogenous distribution of fly ash and SiC particles. Rotating effect of FSW tool results in breaking of some array of grains present in the parent AMCs. Needle like phases present in the parent AMCs eliminated successfully by the incorporation of fly ash particles. Higher hardness is observed in the nugget zone compared to other zones. © 2018 Elsevier Ltd. All rights reserved.
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    Studies on microstructure and mechanical characteristics of as cast AA6061/SiC/fly ash hybrid AMCs produced by stir casting
    (Elsevier Ltd, 2020) Patil, S.; Narendranath, S.; Dupadu, D.
    Fly ash has been receiving the extensive concentration as a strong reinforcing element for Aluminum Matrix Composites (AMCs) to strengthen the properties and cut the price of manufacturing. AA6061 reinforced with various weight percentages of fly ash particulates and a constant weight percentage of SiC were prepared by stir casting technique as it is one of the simplest and cost-effective method for producing AMCs. Wettability of SiC and Fly ash particles with the aluminum was enhanced by fly ash itself. The microstructure, hardness and tensile properties of manufactured AMCs were analyzed. Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) discovered a harmonized dispersion of SiC and fly ash particles with superior bonding with the matrix material. The inclusion of fly ash particles in to aluminum matrix enhanced the microhardness and Ultimate Tensile Strength (UTS) of the AMCs. © 2019 Elsevier Ltd. All rights reserved.
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    Multiple response optimisation of process parameters during drilling of GFRP composite with a solid carbide twist drill
    (Elsevier Ltd, 2020) Bhat, R.; Mohan, N.; Sharma, S.; Dayananda Pai, D.; Kulkarni, S.M.
    The article focuses on investigating the effect of operational parameters like feed and speed along with the composite material thickness on the damages caused in the glass fibre reinforced polymer (GFRP) composites during the drilling process. The GFRP composite studied in the presented work comprises E-glass fibre as the reinforcing material and the marine-grade isophthalic polyester as the binding matrix. Multiple responses considered in work comprises Peel-up delamination, push-down delamination and surface roughness. The technique for order of preference by similarity to ideal solution (TOPSIS) is used to develop the performance index and optimise the multiple response problem. Stepwise analysis of variance (S-ANOVA) is used to investigate the significance of each input parameter. The interaction effects of the variables are investigated using the response surface plots. The results indicate that the composite thickness contributes maximum towards the variance in the overall performance index (21.30%) and the optimum combination obtained using TOPSIS approach within the experimental limits for the selected GFRP is N3f1t1 with the maximum value of Pi (0.888). The regression model developed proves to have high goodness of fit with just 6.01% average error between predicted and experimental values. © 2019 Elsevier Ltd.
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    Effect of traverse speed on joint characteristics of FSWed HAMCs
    (Elsevier Ltd, 2020) Patil, S.; Narendranath, S.; Dupadu, D.
    The present work describes the evolution of microstructure and enhancement of mechanical properties of friction stir welded AA6061/SiC/FA Hybrid AMCs (HAMCs). Various joints were produced using different traverse speed from 30 mm/min to 80 mm/min. Microstructural analysis was carried out using Optical microscopy and scanning electron microscopy. Mechanical characteristics such as ultimate tensile strength (UTS) and microhardness (Hv) were studied. Sound quality joints were obtained by FSW without any defects. Results showed that the microstructure zones are divided in to nugget zone, thermomechanically affected zone, heat affected zone and base material zone. Uniform and fine grain formation took place at traverse speed of 60 mm/min indicating sufficient amount of heat input at this speed. Accordingly maximum joint efficiency of 90% is obtained at this traverse speed. © 2020 Elsevier Ltd. All rights reserved.
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    Comparative study of natural fibre 3D braided yarn woven fabric and simply twisted yarn woven fabric reinforced epoxy composites
    (American Institute of Physics Inc. subs@aip.org, 2020) Kanakannavar, S.; Jeyaraj, P.
    In this study natural fibre 3D braided yarn plain woven fabric (NFBF) and natural fibre simply twisted yarn plain woven fabric (NFSF) are prepared and tensile tests are conducted on braided yarn, simply twisted yarn, NFBF and NFSF. Then the tensile results of braided yarn compared with simply twisted yarn and NFBF results with NFSF. The composites are manufactured by reinforcing prepared fabrics (NFBF and NFSF) with the epoxy resin. On these composites tensile and flexural properties characterisation is carried out in warp and weft directions of the fabrics. SEM analysis is used for fractured surface study. The test results showed that, simply twisted yarn and its fabrics (NFSF) are presented better strength than that of the braided yarn and its fabric (NFBF). The NFSF/epoxy composite in warp direction loading received higher tensile strength and flexural strength of about 67.12 MPa and 131 MPa. © 2020 Author(s).
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    A Sustainable Approach to Turn Plastic Waste into Useful Construction Blocks
    (Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Monish, K.; Jesuran, J.J.; Kolathayar, S.
    The world economy is surging and newer technologies are evolving with the time. The construction sector is about to undergo a huge transformational change. The people of the world are looking forward to residing in houses made of sustainable materials. The people are concerned about increasing levels of greenhouse gases in the atmosphere. The cement production is accompanied by huge greenhouse gas emissions. On the other hand, waste plastics are becoming a nightmare for the people residing in developed and underdeveloped countries, as the waste management becomes difficult in those places. This research discusses a potential solution to address the above-stated issues of concern, i.e., plastic waste into construction blocks with lower cost and rapid construction phases. A study was conducted to examine the effectiveness of using LDPE (Low-Density Polyethylene), (major sources of waste and least recycled plastic) with waste materials like bottom ash, copper slag, and ceramic in different proportions to create blocks. This study compares the mechanical properties of different mix proportions of raw materials to find an optimum composition. This paper also investigates the pre-eminence of the newly developed composite block over the conventional brick in terms of economic viability, environmental sustainability, and construction superiority. © 2021, Springer Nature Singapore Pte Ltd.
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    A review of various materials for additive manufacturing: Recent trends and processing issues
    (Elsevier Editora Ltda, 2022) Srivastava, M.; Rathee, S.; Patel, V.; Kumar, A.; Koppad, P.G.
    Tremendous growth has been witnessed in the field of additive manufacturing (AM) technology over the last few decades. It offers a plethora of applications and is already being utilized in almost every sphere of life. Owing to inherent differences between each AM technique, newer fields of research consistently emerge and demand attention. Also, the innovative applications of AM open up newer challenges and thus avenues for focused attention. One such avenue is AM materials. Raw material plays an important role in determining the properties of fabricated part. The type and form of raw material largely depend on the type of AM fabricators. There is a restriction on material compatibility with most of the established AM techniques. This review aims to provide an overview of various aspects of AM materials highlighting the progress made especially over the past two decades. © 2022 The Author(s).
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    Analysis of piezoelectric composite beams and plates with multiple delaminations
    (2006) Raja, S.; Prathima Adya, H.P.; Viswanath, S.
    In the present work, the effect of delamination or debonding on the static and dynamic characteristics of laminated piezoelectric beams and plates is studied. A four-noded quadrilateral shear flexible plate element is developed to model the damages in composite substrate and in piezoelectric layers. The elastic stiffness and electro-elastic stiffness degradations are introduced at the elemental level through coupled constitutive relations. The undamaged structure is modeled as a single laminate while the delaminated region is modeled as sublaminates whose interface contains the desired delamination or debonding. The continuity of displacement is maintained across the delaminated edge by imposing the strain-based multipoint constraints. Numerical studies are conducted on composite specimens with surface bonded active layers. The results are presented to evaluate the performance of these smart structures in the presence of delamination. For actuators, the performance is measured in terms of the achievable deflection control and in sensors as a measurable output voltage. It is observed that actuator and sensor debonding degrade the capabilities of active materials significantly. Therefore, the study concludes that a damage tolerant approach is essential for the design of smart structural systems to account for damage-induced uncertainty in the functional properties of smart actuators and sensors. Copyright © 2006 SAGE Publications.