Faculty Publications
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Item Examining the Influence of StackinSequence on the Mechanical Properties of Hybrid Abaca-Jute Vinyl Ester Composites(Springer Nature, 2024) Ramesh, S.; Maruthi Prashanth, B.H.; Anne, G.; Naik, G.M.; Reddy, R.; Jagadeesh, C.; Sharma, P.; Prashanth Pai, M.This research looked on the impacts of layer arrange-ment on inter-laminar shear strength (ILSS), tensile, flexural, and impact capabilities of hybrid composite developed from 25% abaca and 25% jute fabrics reinforced 50% vinyl ester. Furthermore, the samples frac-tured under the tensile load were examined using SEM images. Utilizing a hot press process, these hybrid laminates were fabricated and sample preparation and testing were done as per ASTM criteria. The findings demonstrate that among Abaca-Jute-Abaca-Jute (AJAJ), Abaca-Jute-Abaca (AJJA), and Jute-Abaca-Abaca-Jute (JAAJ) vinyl ester composites, the Abaca-Jute-Jute-Abaca (AJJA) composites showed higher tensile modulus and strength by 23–33%, the flexural modulus and strength by 3–22%, the impact behavior, and ILSS strength by 11–33%. These benefits could be attributed to the presence of abaca fiber on the exterior of lami-nates. Fractography studies revealed that the fiber-resin bonding was superior. AJJA composites were found to be stronger than commonly used plastics in automobile interiors, making them a promising alternative. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Item A comparison of the effects of microwave versus conventional drying on the mechanical properties distribution of dried green porcelains(2008) Hemanthakumari, P.N.; Satapathy, L.N.The effect of fast microwave drying of electroporcelain insulator component was studied by determining the reliability parameter. The Weibull modulus was calculated using the three-point bend strength data of a large number of green samples which were dried using microwave energy. The results were compared with those obtained by conventional drying methods. It was observed that in most cases, microwave-dried components yielded higher Weibull modulus than their conventionally dried counterparts. A high modulus value of >15 was achieved on the microwave-dried samples. The analysis of the result was useful in understanding the fast drying process in ceramics. © 2008 The American Ceramic Society.Item Strength deformation behaviour of circular concrete filled steel tubes subjected to pure bending(2009) Chitawadagi, M.V.; Narasimhan, M.C.The strength deformation behaviour of circular steel tubes filled with different grades of concrete under flexure is presented. The effects of steel tube thickness, the cross sectional area of concrete, strength of in-filled concrete and the confinement of concrete on moment capacity and curvature of Concrete Filled steel Tubes (CFTs) are examined. Measured flexural strengths are compared with the values predicted by EC4-1994 and LRFD-AISC-1999 code provisions. A total of ninety nine specimens, all one metre long, were tested with concrete fills of 20, 30 and 40 N/mm2 characteristic strength and with D / t ratio 22.3 to 50.8. Based on the experimental results, an interaction model to predict moment and curvature of the CFT sample is developed. © 2009 Elsevier Ltd. All rights reserved.Item Behavior of sandwich beams with functionally graded rubber core in three point bending(2011) Doddamani, M.R.; Kulkarni, S.M.; KishoreThe three-point bending behavior of sandwich beams made up of jute epoxy skins and piecewise linear functionally graded (FG) rubber core reinforced with fly ash filler is investigated. This work studies the influence of the parameters such as weight fraction of fly ash, core to thickness ratio, and orientation of jute on specific bending modulus and strength. The load displacement response of the sandwich is traced to evaluate the specific modulus and strength. FG core samples are prepared by using conventional casting technique and sandwich by hand layup. Presence of gradation is quantified experimentally. Results of bending test indicate that specific modulus and strength are primarily governed by filler content and core to sandwich thickness ratio. FG sandwiches with different gradation configurations (uniform, linear, and piecewise linear) are modeled using finite element analysis (ANSYS 5.4) to evaluate specific strength which is subsequently compared with the experimental results and the best gradation configuration is presented. © 2011 Society of Plastics Engineers.Item Flexural fatigue analysis of steel fibre reinforced concrete(2012) Girish, M.G.; Chandrashekar, A.; Ravi Shankar, A.U.This paper presents the experimental investigation carried on Steel Fiber Reinforced Concrete (SFRC) subjected to repeated loading. The SFRC beam specimen of size 500mm × 100mm × 100mm containing mixed steel fibers of size 50mm × 2mm × 0.6mm and 0.5mm?× 30mm in different proportions were tested under two point flexural fatigue load at a frequency of 2Hz at various stress levels. The readings obtained from the flexural fatigue test were used to plot S-N diagram and also to perform statistical analysis using two parameter Weibull distributions. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.Item Compressive and flexural properties of functionally graded fly ash cenosphere-epoxy resin syntactic foams(John Wiley and Sons Inc, 2015) Doddamani, M.; Kishore; Shunmugasamy, V.C.; Gupta, N.; Vijayakumar, H.B.The present study focuses on developing functionally graded syntactic foams (FGSFs) based on a layered co-curing technique. The FGSFs were characterized for compressive and flexural properties and compared with plain syntactic foams. The results showed that the specific compressive modulus was 3-67% higher in FGSFs compared to plain syntactic foams. FGSF exhibited 5-34% and 34-87% higher specific modulus and strength, respectively in flexural mode. The microscopic examinations of comparative responses of the filler and matrix to deformation suggest that the failure is dominated by the matrix. The gradient in the composition of syntactic foams helps in effectively distributing the stress throughout the microstructure and results in improved mechanical performance of syntactic foams. From the microscopy studies, it is evident that, the failure mechanism in the FGSF under flexural loading is governed by a crack that initiated on the tensile side of the specimen and propagated through the thickness to cause complete fracture. The microscopic observations further clearly demonstrate the existence of seamless interfaces between the layers and a clear difference in the cenosphere concentration across the interface, affirming the gradation in the prepared samples. The results show that appropriate compositions of FGSFs can be selected to develop materials with improved mechanical performance. © 2014 Society of Plastics Engineers.Item Effect of particle surface treatment and blending method on flexural properties of injection-molded cenosphere/HDPE syntactic foams(Springer New York LLC barbara.b.bertram@gsk.com, 2016) Bharath Kumar, B.R.; Doddamani, M.R.; Zeltmann, S.E.; Gupta, N.; Uzma; Gurupadu, S.; Sailaja, R.R.N.The present work on cenosphere/high-density polyethylene (HDPE) syntactic foams aims at understanding the effect of surface treatment of cenospheres and functionalization of HDPE on flexural properties. Cenospheres are treated with silane, and HDPE is functionalized with 10 % dibutyl maleate. Effects of mechanical and Brabender mixing methods are also studied. Flexural test specimens are cast with 20, 40, and 60 wt% of cenospheres using injection molding. The flexural modulus and strength are found to increase with increasing cenosphere content. Particle breakage increases with the cenosphere content, and the measured properties show increased dependence on processing method. Brabender mixing resulted in 70 and 41 % higher modulus and strength for 60 wt% cenospheres than HDPE. Modulus of syntactic foams is predicted by two theoretical models. Bardella–Genna model provides close estimates for syntactic foams having 20 and 40 wt% cenospheres, while predictions are higher for higher cenosphere content, likely due to particle breakage during processing. The uncertainty in the properties of cenospheres due to defects contributes to the variation in the predicted values. © 2015, Springer Science+Business Media New York.Item Effect of arctic environment on flexural behavior of fly ash cenosphere reinforced epoxy syntactic foams(Elsevier Ltd, 2018) Garcia, C.D.; Shahapurkar, K.; Doddamani, M.; Mohan Kumar, G.C.M.; Prabhakar, P.In this paper, the effect of arctic conditions on the flexural response of cenosphere/epoxy syntactic foams is investigated. Understanding the behavior of such foams under extreme conditions is critical for exploring their suitability for constructing lightweight platforms used in arctic explorations. Such platforms are exposed to subzero temperatures for extended periods of time potentially degrading their mechanical properties. In the research study presented here, samples of cenosphere/epoxy syntactic foams were conditioned under arctic environment at ?60 °C temperature for a period of 57 days. Flexural tests were then conducted at room temperature as well as in-situ ?60 °C on the conditioned samples and compared against unconditioned samples. Combinations of surface modification and cenosphere volume fractions were considered. Experimental findings showed that an increase in flexural modulus can be observed at room temperature with increasing cenosphere volume content for both untreated and treated cenosphere reinforced syntactic foams. In contrast, a decrease in flexural strength was observed as compared to neat resin. For the case of arctic exposed samples, an apparent increase in flexural modulus was recorded between 7-15% as compared to room temperature cenospheres/epoxy syntactic foams. In addition, an apparent increase of 3–80% in the flexural strength was observed under arctic environment. The conditioning of cenosphere/epoxy syntactic foams under low temperatures manifested lower strains to failure as compared to neat epoxy and they exhibit quasi-brittle behavior leading to sudden failure in the post peak regime. © 2018 Elsevier LtdItem 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 Optimization of Process Parameters by Taguchi Grey Relational Analysis in Joining Inconel-625 Through Microwave Hybrid Heating(Springer New York LLC barbara.b.bertram@gsk.com, 2019) Badiger, R.I.; Narendranath, S.; Srinath, M.S.The quality of welded joints developed using microwave hybrid heating (MHH) technique is largely influenced by properties of the constituents employed in the process. This article investigates the influence of process parameters on tensile strength and flexural strength of Inconel-625 plates welded through MHH. Experiments were planned according to Taguchi L 16 orthogonal array by considering three factors: separator, susceptor and filler powder particle size. Ultimate tensile strength and flexural strength of the specimens welded at 600 and 900 W were chosen as response characteristics. Application of Taguchi-based GRA has been effectively used to optimize multi-performance characteristics of the process. ANOVA results indicate that size of interface filler powder is the most significant factor in determining the joint strength followed by separator and susceptor. Further to corroborate the optimal parameter setting for maximum strength values, metallurgical characterization of the specimens is carried out through XRD and SEM. Specimens processed at 600 W exhibited superior properties compared to their counterparts developed at 900 W. © 2018, Springer Science+Business Media, LLC, part of Springer Nature and ASM International.