Faculty Publications
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Item Study on effect of incorporation of SiC fillers on tensile and flexural behavior of GV composites by experimental and simulation methods(2008) Surendranathan, A.O.; Savitha, M.; SreenivasaPrasad, K.V.Characterization of engineering properties is a complex issue for fiber- reinforced composites due to their inherent anisotropy and in homogeneity. In terms of mechanical properties, advanced composite materials are evaluated by a number of specially designed test methods. In this study the incorporation of SiC fillers on Mechanical behavior of Glass-Vinyl ester (G-V) composites has been investigated. The composites are assessed by using J.J. Lloyd UTM. The properties like tensile strength, modulus, elongation at break, and flexural strength were investigated as per ASTM standards. From the experimental investigation, it is found that the tensile and flexural strength of G-V composites increased with increasing the SiC content. Also simulation of both tensile and flexural properties of GV composites with and without SiC fillers has been carried out to validate the experimental results. The fractured surfaces of G-V composites are observed using Scanning Electron Microscope (SEM) to reveal the results. © 2008 MS&T08.Item Microbial effects on heat treated 316L weldments in marine water(2013) Suvarna, K.; Udupa, K.R.; Surendranathan, A.O.Austenitic stainless steels are susceptible to microbiologically influenced corrosion (MIC) when they are in contact with sea water. This is due to the changes in the chemistry of the environment at the metal surface because of the settlement and activities of microorganisms. The thrust of our work was in understanding the changes in the electrochemical behaviour of a type 316L stainless steel in the presence of a natural biofilm as well as the influence of metallurgical characteristics on microbial adhesion and MIC. The presence of a biofilm on material surface can influence the corrosion behaviour since the value of a given parameter such as temperature, pressure, concentration of a solute and pH at the water /substrate interface under the biofilm may be different from that in the bulk environment. The non-uniform nature of biofilm thus helps in generating heterogeneity in the environment at the surface. Thus, biofilms are known to aid in the initiation of corrosion, change the mode of corrosion or cause changes in the corrosion rate. Bacteria Arthobacter nicotinae (An) and algae Chlorella pyrenoidosa (Cp) were used for the study and bio film formed due to these showed pit initiation and increase in corrosion rate as time proceeds. 316L base metal (BM) and weld metal (WM) as received and after heat treated at 450°C for 10000 hours were studied and corrosion evaluation was done. Heat treated WM showed severe response to corrosion compared to as received WM. © (2013) Trans Tech Publications, Switzerland.Item Mechanical and tribological behaviour of epoxy reinforced with nano-Al2O3 particles(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Kurahatti, R.V.; Surendranathan, A.O.; Ramesh Kumar, A.V.; Auradi, V.; Wadageri, C.S.; Kori, S.A.In the present work systematic study has been conducted to investigate the matrix properties by introducing nanosize Al2O3 (particle size 100 nm, 0.5-10 wt %) fillers into an epoxy resin. High shear mixing process was employed to disperse the particles into the resin. The experimental results indicated that frictional coefficient and wear rate of epoxy can be reduced at rather low concentration of nano-Al2O3. The lowest specific wear rate 0.7 × 10-4 mm3/Nm is observed for the composites with 1 wt.% which is decreased by 65% as compared to unfilled epoxy. The reinforcement of Al2O3 particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © (2014) Trans Tech Publications, Switzerland.Item Study on Mechanical & Cryogenic Properties of Carbon Epoxy Composites(Institute of Physics Publishing helen.craven@iop.org, 2018) Sunil Kumar, B.V.; Neelakantha, N.V.; Surendranathan, A.O.; Anilas, K.Carbon-fiber-reinforced polymers are composite materials. In this case the composite consists of two parts: a matrix and reinforcement. In CFRP the reinforcement is carbon fiber which provides the strength. The matrix is usually a polymer resin such as epoxy to bind the reinforcements together. The material properties depend on these two elements. The reinforcement will give the CFRP its strength and rigidity measured by stress and elastic modulus respectively. Unlike isotropic materials like steel and aluminium CFRP has directional strength properties. The properties of CFRP depend on the layouts of the carbon fiber and the proportion of the carbon fibers relative to the polymer. This paper deals with the studies done on cryogenic treatment (Liquid Nitrogen) of composites having different fiber and matrix composition. In this work studies are done to find the effects caused by the liquid nitrogen on composites mechanical properties and change in properties due to different fiber and matrix composition in composites. It was observed that due to cryogenic treatment there was changes in the physical properties of the specimens. The specimens had deformed in their shape. The more deformation was seen in 60:40 specimen which was treated for 48 hrs and tensile strength of the composites at cryogenic temperature had higher values than that normal temperature for 70:30 specimen which was treated for 24hrs. The flexure strength of the composites at cryogenic temperature had higher values than the normal temperature for all the specimens. The flexure strength is more for 70:30 specimen which was treated for 48hrs. © Published under licence by IOP Publishing Ltd.Item Space-quality reinforced polymer-composites permitting travelling-magnetic-fields in new Indus-Hypersonic-Loop(American Institute of Physics Inc. subs@aip.org, 2019) Karkera, B.N.; Surendranathan, A.O.; Sinha, A.This paper specifies polymer composites for dual usages, namely (a) internal lining of thousands of kilometer long transfer-tubes; and (b) external lining of 16.5-meter-long passenger-capsules. These are the two primary components of intercontinental Indus-Hypersonic-Loop recently proposed by authors. Their innovative ideas specify advanced features of composites, namely (1) space quality polymer composites for longevity operations; (2) adequate reinforcement to withstand peeling force of 10 tons/sq. m on both the linings; (3) excellent nonmagnetic property for creating efficient travelling magnetic field and their interactions between transfer-tube and passenger-capsule; and finally (4) strong bond-ability with electromagnetic-bodies. Having strong adhesive of polymer-composites, the passenger-capsule must withstand bursting load of ∼1,500 tons; and transfer-tube must withstand collapsing load of 100tons/running 100m. The authors have theorized, analyzed and invented four ideas namely (i) travelling magnetic fields along the transfer-tube by ingenious time-space separation of these fields; permitting sub-sonic, supersonic and hypersonic velocities for travels within nations, between nations and between continents; (ii) magnetodynamic bottling, made possible with the help of inductive magnetic fields, for preventing the passenger-capsule from rubbing or crashing on to the sides of the transfer-tube; (iii) reduction of air-drag-force by many orders of magnitudes, using 10-3 to 10-6 torr vacuum as spinoff of above bottling; (iv) dynamic power transfer from transfer-tube to passenger-capsule, even at hypersonic velocities; thus altogether eliminating on-board battery banks. © 2018 Author(s).Item Composites with graphene as reinforcement(Institute of Physics Publishing helen.craven@iop.org, 2019) Surendranathan, A.O.In this paper, the developments in the area of graphene-reinforced composite have been reviewed. It also depicts the work guided by the author. In the work, WC powder with 6% cobalt (Co) and graphene (0.2%) in the form of graphene nanoplatelets (GPLs) was prepared by high energy rate ball milling and ultrasonification. The mixture was sintered using spark plasma sintering at 1250°C for 10 min. To study the effects of graphene reinforcement, the sample was analyzed for the physical (density), magnetic (coercivity, and magnetic saturation), microstructural (porosity) and mechanical properties (hardness, fracture toughness). Under Visual Inspection of the Spark Plasma Sintered (SPS) sample, the top surface showed more homogeneous distribution of the constituents than the bottom surface. The results of the surface measurements showed that the top and bottom surfaces have almost the same roughness. It was found that the SPS sample exceeded liquid phase sintered (LPS) specimens with respect to hardness and fracture toughness values. The coercive force was found to be higher for the LPS sample whereas the saturation magnetization value was found to be higher for the SPS sintered specimen. The density value is higher for the LPS sintered specimen. The presence of pores is seen in the back scattered electron (BSE) image. There was certain amount carbon pick up from the graphite die used in SPS. There was uniform distribution of the cobalt binder. The x-ray diffraction pattern for the SPS sintered sample indicates the presence of WC, Co and GNP. © 2019 IOP Publishing Ltd. All rights reserved.Item Effect of plastic strain and processing routes on the hardness of as-cast aluminum(American Institute of Physics Inc. subs@aip.org, 2020) Valder, J.; Rijesh, R.; Kumar, P.; Saminathan, S.; Raju, K.; Surendranathan, A.O.In the present study, Equal Channel Angular Pressing (ECAP) of commercially pure aluminum (Al) in the cast form was carried out at room temperature for assessing its hardness by different routes and passes. The different routes employed in the present investigation are A, BA, BC and C. The Al specimens were pressed by a die of 150° channel angle without back pressure with Molybdenum disulfide (MoS2) as the lubricant. ECAP has significantly improved the hardness of Al in the subsequent passes. It has been observed that the hardness has been increased after first pass at room temperature from 47 VHN in the annealed condition to 54 VHN and after the second pass the hardness value has been increased to 56, 57, 62 and 56 VHN for routes A, BA, BC and C respectively. The increase in the hardness may be attributed to the severe fragmentation of microstructure of cast Al and the change in the orientation of the specimen from one pass to the next pass. After one pass, the dendritic microstructure of cast Al has been distorted by the shear stress developed during deformation. The processing by different routeswith number of passes has further refined the microstructure leading to a better hardness in the cast Al. © 2020 Author(s).Item Experimental investigation on Mode-I fracture toughness of Carbon-Carbon composites fabricated by preformed yarn method(Elsevier Ltd, 2021) Sunil Kumar, B.V.S.; Neelakantha Londe, V.; Lokesha, M.; Anilas, M.; Surendranathan, A.O.Carbon-Carbon composites are one such material that gives designers significant importance for advanced applications over conventional materials. They are applied in applications at very high temperatures (up to 3000°C), and under extreme conditions. They have a density which is much less than metals and ceramics and thus, make low part weight a significant factor for aerospace applications. Fracturing toughness is a measurable way to express a substance's resistance to fracture in the case of a break. This paper describes the experimental studies done to investigate the Mode-1 fracture toughness of carbon-carbon composites which was fabricated via the preformed yarn method. Fracture toughness was determined for four different (a/w) ratios i.e. 0.45, 0.47, 0.50 and 0.52 respectively. The results showed that with only two cycles of pitch impregnation, HIP and graphitizing, carbon-carbon composites were successfully produced. The specimen having an (a/w) ratio of 0.45 had a higher fracture toughness value in comparison with all values. As the (a/w) ratio was increasing, the fracture toughness value decreased and the fractured surface clearly shows a brittle fracture behavior. © 2021 Elsevier Ltd. All rights reserved.Item Study on fracture toughness of carbon-carbon composites at low temperatures(Elsevier Ltd, 2022) Sunil Kumar, B.V.S.; Neelakantha, N.V.; Kumar, M.; Lokesha, M.; Vasantha Kumar, S.N.; Surendranathan, A.O.Carbon-carbon composites (C-CC), employed as composites in space and other industries for their outstanding properties. In extreme temperatures, the C-CC has proved to be the most efficient material. C-CC is one of the top thermal quality high-temperature materials such as high-temperature stability, excellent thermal conductivity, and low-temperature expansion coefficients. C-CC brake disks are highly demanded in aviation, trains, trucks, even race vehicles. Although C-CC is normally utilized at very high service temperatures, recently it has been necessary to explore these in low-temperature circumstances as components must also pass through low-temperature conditions in modern applications. In developing engineering structures, materials and systems for their technical safety, durability, and reliability, fractures and damage prevention and evaluation have an important role to play. Fracture toughness means quantifying the resistance of the fracture when a crack occurs. The present experimental study explores the influence of low temperature on the fracture toughness of C-CC. The low temperatures test of the samples has been done at a temperature between -10 °C and -40 °C. The results demonstrate that the fracture toughness value consistently raised as the temperature dropped. The Fluctuation began at a -10 °C from 2 % with a forecast of -40 °C to 32 %. © 2022 Elsevier Ltd. All rights reserved.Item Defence applications of polymer nanocomposites(Defense Scientific Information and Documentation Centre, 2010) Kurahatti, R.V.; Surendranathan, A.O.; Kori, S.A.; Singh, N.; Kumar, A.V.R.; Srivastava, S.The potential opportunities promised by nanotechnology for enabling advances in defence technologies are staggering. Although these opportunities are likely to be realised over a few decades, many advantages are currently being explored, particularly for defence applications. This review provides an insight into the capabilities offered by nanocomposites which include smart materials, harder/lighter platforms, new fuel sources and storage as well as novel medical applications. It discusses polymer-based nanocomposite materials, nanoscale fillers and provides examples of the actual and potential uses of nanocomposite materials in defence with practical examples. © 2010, DESIDOC.