Faculty Publications
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Item Characterization of porous friction course mixes for different Marshall compaction efforts(2009) Suresha, S.N.; George, V.; Ravi Shankar, A.U.R.Porous friction courses (PFCs) are mainly recommended as surface drainage layers on high-speed road-corridors and runway pavements. Permeability and sound attenuation characteristics are considered to be the indices for performance assessment of PFCs. One of the reasons for the loss of permeability in PFCs is densification under heavy traffic. But, resistance to ravelling too, is of main concern in the case of under-compacted PFCs. This paper summarises the details of laboratory investigation on the characterization of PFC mixes corresponding to four different gradations and two binder contents, for three levels of the Marshall compaction. The findings of the investigation suggest that the selection of the compaction level for PFC mix design should be based on the design traffic level, and the gradation selected. © 2009 Elsevier Ltd. All rights reserved.Item Effect of aggregate gradations on properties of porous friction course mixes(2010) Suresha, S.N.; George, V.; Ravi Shankar, A.U.This paper presents the study on effect of aggregate gradation on the mix design and performance properties of porous friction course (PFC) mixes. Six aggregate gradations were tested with due consideration to gradations specified for PFC or similar mixes by different agencies around the world. The PFC mixes were characterized for volumetric properties, permeability, unaged and aged abrasion loss, moisture susceptibility, and rutting resistance. The results were statistically analysed to identify the factors that significantly influence the properties of PFC mixes. Findings of the study clearly indicate that the gradations specified by various agencies will have significant effect on the design properties of PFC mixes, thus they are different. It also, helps in framing the Master aggregate gradation band for PFC mixes. Generally, permeability property is considered to be an optional parameter in the design. However, the findings of the present study recommended considering the permeability as one of the prime parameters in the design of PFC mixes. © RILEM 2009.Item Abrasive wear behavior of granite-filled glass-epoxy composites by SiC particles using statistical analysis(2011) Basavarajappa, .S.; Manjunath Yadav, S.M.; Kumar, S.; Arun, K.V.; Narendranath, S.This experimental investigation deals with the evaluation of abrasive wear behavior of Glass Epoxy (G-E) composites on pin-ondisc test rig. A plan of experiments, based on the Taguchi Design of Experiments, was performed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the percentage of contribution of various process parameters like sliding speed, applied load, sliding distance and their interactions affecting the abrasive wear volume loss of composites. The correlations between the various factors affecting the abrasive wear behavior of composites were obtained by using multiple linear regression equations. The obtained results indicate that applied load and sliding distance were the wear factors that have the highest physical as well as statistical influence on the abrasive wear behavior of both filled and unfilled G-E composites. A good agreement between the predicted and actual wear resistance was observed within±12%. © Taylor & Francis Group, LLC.Item Mechanical and permeability properties of hybrid fibre reinforced porous concrete(Associated Cement Companies Ltd., 2019) Snehal, K.; Das, B.B.Experimental investigation was carried out to determine the enhancement of compressive strength, flexural strength and abrasion resistance along with water permeability of porous concrete introduced with hybrid fibres (consists of equal proportion of steel, polypropylene and glass) and with two different sizes of coarse aggregate. The varying parameters in the preparation of porous concrete mix were coarse aggregate of two sizes, i.e., 6 mm and 12 mm and five different percentages of hybrid fibres (0.25 - 0.65 with an increment of 0.1). Compressive strength and flexural strength were measured at the end of two curing periods (7 and 28 days) whereas water permeability and abrasion test values were measured at the end of 28 days of curing. From the experimental findings, it is observed that compressive strength and flexural strength values increase with decrease in the size of the aggregate for control as well as fibre reinforced porous concrete. However, with respect to the measured values of permeability, it is found that with increase in size of coarse aggregates, permeability values also increases. For 28 days samples it is observed that 0.35% addition of hybrid fibres to porous concrete found to be optimum and it improved the compressive strength values by 20.24% and 19.06% for coarse aggregate sizes of 6mm and 12mm, respectively as compared to porous control concrete (without addition of hybrid fibres). Whereas, maximum flexural strength was obtained at 0.45% of addition of hybrid fibres and 31.6% (6mm coarse aggregate) increment and 24.26% (12mm coarse aggregate) increment were noticed as compared to porous control concrete. The best values for permeability were found at 0.35% of hybrid fibres and 12 mm coarse aggregate combination, whereas for abrasion resistance it was at 0.35% of hybrid fibres and 6mm coarse aggregate combination. © 2019 Associated Cement Companies Ltd.. All rights reserved.Item Experimental study on Abrasive wear behaviour of flexible green composite intended to be used as Protective Cladding for Structures(ModTech Publishing House office@hotelfloramamaia.ro, 2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.In the present study, the influence of material and process parameters on the two body abrasive wear behavior of Jute-Rubber flexible composite is investigated using Taguchi’s design of experiments (DOE). Three different stacking sequences of composite namely jute-rubber-jute (JRJ), jute-rubber-rubber-jute (JRRJ) and jute-rubber-jute-rubber-jute (JRJRJ) are considered and their wear behavior is evaluated using two body abrasion test with multi-pass condition for abrading distances of 0.4 m to 1.2 m in increments of 0.4 m and varied load of 9.81 N, 12.26 N and 14.71 N. Abrasive volume loss and specific wear rate as function of abrading distance are determined. The results from Taguchi’s design of experiments show that for two body dry sliding wear situation, an abrading distance significantly affects the specific wear rate compared to load and composite configuration. However, volume loss is more and appreciable when jute fabric is exposed to abrasive medium rather than when the rubber is exposed. Surface morphology study is carried out using a scanning electron microscope to get an insight of wear mechanism of constituents of the flexible composite. Stretching of asperities results in wear of the rubber, whereas fiber breakage causes wear of the jute. Rubber being the dominating constituent of flexible composite results in providing better wear resistant properties and thus can act as a potential candidate for sacrificial structures to protect primary structures subjected to wear. © International Journal of Modern Manufacturing Technologies.Item High-temperature wear and frictional behavior of partially oxidized Al with NiCr composite coating(Institute of Physics Publishing helen.craven@iop.org, 2019) Medabalimi, S.R.; Ramesh, M.R.; Kadoli, R.The influence of composite coating in improving wear and frictional behavior from room temperature to 600 °C was investigated. Partially oxidized Al powder was prepared with a flame spray process by spraying pure Al powder into distilled water. The composite powder is the mixture of 30 weight percent of partially oxidized Al and 70 weight percent of NiCr alloy powder. The composite powder was subsequently coated on MDN321 steel by air plasma spray process. The composite coatings are characterized with respect to adhesion strength, porosity, micro-hardness, and density. Wear and frictional behavior of coatings are evaluated under disc speed of 1 and 2 m s-1, loads of 10, 20 and 30 N and 3000 m sliding distance. The test results indicated that at room temperature, frictional heat generated due to applied load produce three-body abrasion at the interface caused to increase the wear and friction in the coating. The oxide film formed at high temperature due to plastic deformation avoids surface degradation at the interface and reduce the wear and friction. The worn surfaces at 600 °C consist phases of ?-Al2O3, NiO, and Cr3O. These phases are contributing to improving the wear resistance of the coating more than 4-times compared to uncoated steels under varying load and sliding velocities. The coefficient of friction reduced with increase in temperature due to generated oxides act as lubricants at the interface. © 2019 IOP Publishing Ltd.Item Effect of low temperature annealing on the properties of nano Ni-Ti alloys(Institute of Physics Publishing helen.craven@iop.org, 2019) Mukunda, S.; Mahesh, M.; Narendranath, S.; Herbert, M.A.Binary 1:1 Ni-Ti alloy has been the work horse for many industrial and of late biomedical applications amongst all shape memory alloys. Apart from being employed for endovascular applications like stents and filters, they are also used as orthodontic braces and in endodontic tools. Ni-Ti drills and files are used in a few procedures with sterilization between uses. However, the effect of these sterilizing heat-treatments on the properties of the tools is not clearly investigated. In addition to this, satisfactory metallurgical explanations for the wear resistance of these alloys in absent in the literature. Therefore, this paper attempts to define the transformational temperatures for the Ni-Ti as-received and low temperature heat-treated conditions have been investigated using Differential Scanning Calorimetry (DSC). Attempts are made to justify their suitability for endodontic applications by evaluating their mechanical strength parameters using the Tensile and Wear tests. It was found that the samples showed did not show much variations in strength when subjected to tensile tests whereas the same was not observed for DSC tests. Ambient temperature x-ray diffraction studies indicate the presence of Austenitic and Martensitic phases in all the samples. DSC results are strongly affected by presence of internal stresses but stress-induced-martensitic forms in all the samples with equal facility. © 2019 IOP Publishing Ltd.Item Tribological Behaviour of Graphite-Reinforced FeNiCrCuMo High-Entropy Alloy Self-Lubricating Composites for Aircraft Braking Energy Applications(Springer New York LLC barbara.b.bertram@gsk.com, 2019) Prabhu, T.R.; Arivarasu, M.; Chodancar, Y.; Arivazhagan, N.; Cadambi, G.; Mishra, R.K.In the present study, the graphite-reinforced FeNiCrCuMo high-entropy alloy-based self-lubricating composites are fabricated through the powder metallurgy. The sintering temperatures (900 and 1000 °C) are varied to study the densification and properties of the composites. The composites are characterized for microstructure, density, and hardness. The brake performance of the composites is evaluated for the braking condition of a military aircraft. The microstructure consists of two phases: one phase (lamella structure) rich with the Fe, Cr, C, and Cu and another white phase rich with the Ni, Cu, C, and Fe along with the uniformly distributed graphite. The EDS analysis confirms the presence of Fe, Cr, Ni, Cu, and Mo in the matrix. The composite sintered at 1000 °C shows improved densification, high hardness, high wear resistance, and excellent braking performance. With the increase of braking energy (speed), the wear rate increases due to the increased intensity of abrasive wear, oxidation wear, and plastic deformation-assisted wear, whereas the friction coefficient has not changed much. Low porosity content and mild abrasive wear are responsible for the high wear resistance in the composite sintered at 1000 °C. Compared to the C/C, C/SiC C/C/SiC composites and Fe- or Cu-based composites, the high-entropy alloy-based composites show great potential for improved braking properties in the high-energy braking applications. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.Item Three body abrasive wear assessment of novel jute/natural rubber flexible green composite(SAGE Publications Ltd, 2021) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.Determining the resistance to abrasion of the flexible cladding for armours and automobile structural components with the aid of lab scale tests has become increasingly important. In the present study, three body wear behaviour of flexible green composites comprising of jute in woven fabric form with interleaved natural rubber sheets bonded through rubberized B stage cured Pre pegs have been studied. Flexible composites are fabricated in three different configurations having different layers of jute and rubber. The present study makes use of silica sand as the abrasive medium. The specific wear rate along with loss in mass and volume of the composite due to wear is determined and it was found that specific wear rate is dependant of the sliding distance. Comparing the specific wear rate of all the three stacking sequences, it was found that JRJ stacking sequence provides better wear resistance. Compliant and tough nature of the rubber makes it hard to wear it out through tearing action and also the wear resistance of flexible composites is enhanced with inclusion of rubber. Mechanism of wear in each of the constituent used is studied. The present study serves as a benchmark work for the future research in this area. © The Author(s) 2021.Item Experimental study on two-body and three-body abrasive wear behaviour of jute-natural rubber flexible green composite(SAGE Publications Ltd, 2023) Mahesh, V.; Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.The use of laboratory testing has become more significant to assess abrasion resistance in flexible reinforcement of armour and car structural components. In this study, compliant composite with constituents as woven jute fabric and natural rubber encapsulated in an NR-based B stage cured prepreg were tested for wear due to abrasion under two- and three-body conditions. Flexible composites are fabricated in three different configurations namely Jute/Rubber/Jute, Jute/Rubber/Rubber/Jute and Jute/Rubber/Jute/Rubber/Jute. The present study makes use of abrasive paper with a grit size of 60 and silica sand with size 250 μm as the abrasive medium for two- and three-body abrasion tests, respectively, and the specific rate of wear is calculated. Though the wear trend of the composites follows a similar pattern in the case of two- and three-body wear, the mechanisms governing the wear are found to be different. The morphology of the worn surface is studied with the aid of a scanning electron microscope. © The Author(s) 2022.