Faculty Publications
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Item Dynamic impact behavior of syntactic foam core sandwich composites(DEStech Publications Inc. info@destechpub.com, 2018) Breunig, P.; Damodaran, V.; Shahapurkar, K.; Waddar, S.; Doddamani, M.; Jeyaraj, P.; Mohan Kumar, G.C.M.; Prabhakar, P.Sandwich composites and syntactic foams have historically been used in many engineering applications to meet the needs of a system. However, there has been minimal effort to take advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of the structure. The goal of this experimental study is to investigate the mechanical response and damage mechanisms associated with sandwich composites with syntactic foam cores. The core was manufactured using epoxy resin as the matrix and cenospheres as the reinforcement with varying volume fractions of 0%, 20%, 40%, and 60%. The sandwich composites were manufactured with the vacuum assisted resin transfer molding (VARTM) process. Impact tests were performed on the specimens according to ASTM D7766 at two energy levels: 80J and 160J. The data from the tests was post-processed to gain quantitative understanding of the damage mechanisms present in the specimens. A qualitative understanding was obtained through MicroCT scanning imaging. The analysis showed that increasing the volume fraction of cenospheres in the syntactic foam made the damage mechanism more desirable, even at high energy levels. © 2018 by DEStech Publications, Inc. All rights reserved..Item Tensile behavior of cenosphere/epoxy syntactic foams(American Institute of Physics Inc. subs@aip.org, 2018) Shahapurkar, K.; Doddamani, M.; Mohan Kumar, G.C.Tensile behavior of syntactic foam composites are very critical to the engineering applications. The fracture modes and failure mechanisms under tension must be fully understood in order to realize the potential of such composites. In the present work, syntactic foam composites are fabricated using as received and surface modified hollow cenospheres embedded into epoxy matrix. Combinations of cenosphere volume fraction (0, 20, 40 and 60%) and surface modification are studied. Experimental results reveal that modulus of both untreated and treated syntactic foams increases with increase in cenosphere volume fraction compared to neat resin. Strength values of syntactic foams show decreasing trend compared to neat resin. However, treated syntactic foams demonstrated better results compared to untreated ones attributing to good bonding between matrix and filler. Scanning electron microscopy reveal brittle fracture for all the syntactic foams. © 2018 Author(s).Item Factors affecting the solid particle erosion of environment pollutant and natural particulate filled polymer composites—A review(SAGE Publications Ltd, 2021) Shahapurkar, K.; Darekar, V.; Banjan, R.; Nidasosi, N.; Soudagar, M.E.M.Solid particle erosion of polymer matrix composites filled with naturally available and environment pollutant fillers have not been studied to the same level as for metals or ceramics and is focus of the present study. In this article, review of the research associated with the erosion response of polymer composites is presented. Particulate polymer composites are employed extensively owing to their enhanced specific properties and tribological response. Particulate filler particles such as environmental pollutants and naturally available ones need to be effectively incorporated in utilitarian applications so as to reduce land fill burden issues and other specific problems. Nevertheless, adequate data is not available in review articles on the erosion of fillers that are environment pollutants and thereby an ample amount of research can be carried out in this regard. Erosion behavior of polymer composites in particular has gained a lot of attention among researches in the recent decade. Viability of incorporating various fillers in polymer matrix for erosion resistive applications needs to be assessed so that the potential of these composites can be well understood. Therefore in this study, erosion response of polymer composites reinforced with fillers is reviewed with a focus on input parameters (impact velocity, impingement angle and erodent properties) and material properties (density). © The Author(s) 2020.Item Compressive behavior of cenosphere/epoxy syntactic foams in arctic conditions(Elsevier Ltd, 2018) Shahapurkar, K.; Garcia, C.D.; Doddamani, M.; Mohan Kumar, G.C.; Prabhakar, P.In this paper, the effects of arctic condition on the compressive response of ceno-sphere/epoxy syntactic foams are investigated. Understanding the behavior of such foams under extreme conditions is critical for exploring their suitability for constructing lightweight platforms used in arctic explorations, which 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 a temperature of ?60 °C for a period of 57 days. Compression tests were then conducted at room temperature as well as in-situ ?60 °C on the conditioned samples and compared against unconditioned samples tested at room temperature. Combinations of surface modification and cenosphere volume fractions were considered. For the case of unconditioned samples, compressive strength decreased with increasing cenosphere volume fraction for both surface modified and unmodified cenospheres. For the arctic conditioned samples, cenospheres/epoxy foams did not present visible signs of degradation prior to testing, but manifested a reduction in compressive modulus in a range of 47–57% and 47–65% for untreated and treated cenospheres/epoxy syntactic foams as compared to their unconditioned counterparts. On the other hand, the compressive strength increased in a range between 32–68% for untreated and 59–80% for treated cenosphere foams in arctic environment, which can be attributed to the matrix hardening introduced by frigid in-situ environment. Also, under in-situ arctic compressive loading, the post peak response for all foam types have shifted from a progressive failure to a brittle type behavior. © 2017 Elsevier LtdItem 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 Influence of surface modification on wear behavior of fly ash cenosphere/epoxy syntactic foam(Elsevier Ltd, 2018) Shahapurkar, K.; Chavan, V.B.; Doddamani, M.; Mohan Kumar, G.C.M.The present study deals with investigating the surface modification effect of fly ash cenosphere (as received and surface treated) on the friction and wear response of epoxy syntactic foams. Such lightweight syntactic foams have the potential in using them as tribo-materials for friction applications like in brake pad composites. This study also addresses the environmental linked disposal issues of fly ash cenospheres by incorporating them (up to 60 vol%) in the epoxy matrix. Cenosphere content and surface modification influence on the friction and wear response of cenosphere/epoxy syntactic foams is investigated against EN31 steel disc under dry sliding conditions. Wear behavior is studied at room temperature for different velocities (2 and 5 m/s), applied loads (30 and 50 N) and sliding distances (3, 5 and 7 km). Neat epoxy exhibits maximum wear rate as compared to foams. Wear rate decreases with increasing sliding distance and cenosphere content at all tested conditions. With the increase in the applied load and the sliding velocity, higher wear rate is noted for neat epoxy samples while it decreases with increasing filler loading. Surface modified cenosphere reinforced foams exhibit better wear resistance compared to as received cenosphere dispersed foams and neat epoxy for all the operating conditions owing to the good interfacial bonding of treated cenospheres with epoxy matrix. Specific wear rate decreases significantly with an increase in applied load. Further, the coefficient of friction decreases with higher filler loading and surface modifications. Scanning electron microscopy is used to study the wear mechanisms. Wear debris is analyzed and disc temperature is also reported. Finally, wear rate results are summarised and compared with the data available from literature and are presented in a property map. © 2018 Elsevier B.V.Item Effect of cenosphere filler surface treatment on the erosion behavior of epoxy matrix syntactic foams(John Wiley and Sons Inc. cs-journals@wiley.com, 2019) Shahapurkar, K.; Doddamani, M.; Mohan Kumar, G.C.; Gupta, N.Influence of cenosphere surface modification and volume fraction on the solid particle erosion of cenosphere/epoxy syntactic foams is investigated. Fly ash cenospheres are used as filler in both as received and silane surface modified configurations. Erosion behavior is studied at room temperature for different impact angles (30, 45, 60, and 90°) and velocities (30, 45, and 60 m/s). Neat epoxy shows the highest erosion rate compared with that of the syntactic foams. Results show a strong dependence of impact angle and velocity on erosion rate of syntactic foams. With increasing cenosphere content erosion rate decreases for all impact angles. Erosion rate decreases with increasing impact angle and with decreasing velocity. Good interfacial bonding of treated cenospheres enhances the erosion resistance. All the samples exhibit ductile erosive behavior, with maximum erosion at 30°. The velocity exponent and erosion efficiency parameters confirm the ductile behavior of syntactic foams. POLYM. COMPOS., 40:2109–2118, 2019. © 2018 Society of Plastics Engineers. © 2018 Society of Plastics EngineersItem Dynamic impact behavior of syntactic foam core sandwich composites(SAGE Publications Ltd info@sagepub.co.uk, 2020) Breunig, P.; Damodaran, V.; Shahapurkar, K.; Waddar, S.; Doddamani, M.; Jeyaraj, J.; Prabhakar, P.Sandwich composites and syntactic foams independently have been used in many engineering applications. However, there has been minimal effort towards taking advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of structures. To that end, the goal of this study is to investigate the mechanical response and damage mechanisms associated with syntactic foam core sandwich composites subjected to dynamic impact loading. In particular, this study investigates the influence of varying cenosphere volume fraction in syntactic foam core sandwich composites subjected to varying dynamic impact loading and further elucidates the extent and diversity of corresponding damage mechanisms. The syntactic foam cores are first fabricated using epoxy resin as the matrix and cenospheres as the reinforcement with four cenosphere volume fractions of 0% (pure epoxy), 20%, 40%, and 60%. The sandwich composite panels are then manufactured using the vacuum assisted resin transfer molding process with carbon fiber/vinyl ester facesheets. Dynamic impact tests are performed on the sandwich composite specimens at two energy levels of 80 J and 160 J, upon which the data are post-processed to gain a quantitative understanding of the impact response and damage mechanisms incurred by the specimens. A qualitative understanding is obtained through micro-computed tomography scanning of the impacted specimens. In addition, a finite element model is developed to investigate the causes for different damage mechanisms observed in specimens with different volume fractions. © The Author(s) 2019.Item Optimum location and influence of tilt angle on performance of solar PV panels(Springer Science and Business Media B.V., 2020) Khan, T.M.; Soudagar, M.E.M.; Kanchan, M.; Afzal, A.; Banapurmath Nagaraj, N.R.; Akram, N.; Mane, S.D.; Shahapurkar, K.With the growing demand of economically feasible, clean, and renewable energy, the use of solar photovoltaic (PV) systems is increasing. The PV panel performance to generate electrical energy depends on many factors among which tilt angle is also a crucial one. Among hundreds of research work performed pertinent to solar PV panels performance, this work critically reviews the role of tilt angles and particularly locating the optimum tilt angle using different methods. The past data collected for analysis can be categorized mainly into mathematical model based, experimental based, simulation based, or combination of any of these. Single-axis tracking, dual-axis tracking, simple glass cover, hydrophobic glass cover, soiled glass, clean glass, partial shadow, use of phase-change material, computational fluid dynamic analysis, etc., are the novel methods found in the literature for analysis and locating the optimum tilt angle. For illustration purpose, few figures are provided in which the optimum tilt angle obtained on monthly, seasonally, and annual basis is shown. Research works are growing in the field of computations and simulations using online software and codes. Pure mathematical-based calculations are also reported but the trend is to combine this method with the simulation method. As the PV panel performance is found to be affected by number of parameters, their consideration in any single study is not reported. In future, work is required to carry out the experiment or simulation considering the effect of soiling, glass material, temperature, and surrounding ambience on the location of optimum tilt angle. As a whole, the optimum tilt angles reported for locations exactly on the equator line, i.e., 0° latitude, ranges between ? 2.5° and 2.5°, for locations just above the equator line, i.e., latitude 2.6°–30° N ranges between 5° and 28°, for 40°–70° N, it is 29°–40°, and for 71°–90° N, it is 41°–45°. For locations at 2.6°–30° S, optimum tilt angles range between ? 4° and ? 32°, 30°–46° S, it is ? 33° to ? 36°, 47°–65° S, it is ? 34° to ? 50°, and for 66°–90° S it is ? 51° to ? 62°. © 2019, Akadémiai Kiadó, Budapest, Hungary.Item Leverage of weave pattern and composite thickness on dynamic mechanical analysis, water absorption and flammability response of bamboo fabric/epoxy composites(Elsevier Ltd, 2023) Kanaginahal, G.M.; Hebbar, S.; Shahapurkar, K.; Alamir, M.A.; Tirth, V.; AlArifi, I.M.; Sillanpӓӓ, M.; Murthy, H.C.A.Spar caps, which cover 50% of the cost of windmill blades, were made of unidirectional and biaxial glass/carbon reinforcements of 600 gsm with thicknesses ranging from 100 to 150 mm for blades 70–80 m long. The significance of this study was to utilize an economical biodegradable material i.e bamboo fabric of 125 gsm to fabricate a lightweight composite and study its behavior for spar caps applications. The aim of this research was to investigate the effect of weave pattern and composite size at coupon level under thermal, dynamic, water absorption, and flammability conditions. Composites comprising 125 gsm plain and twill weave bamboo as reinforcements/AI 1041 Phenalkamine bio-based hardener with epoxy B-11 as matrix were tested. Thermo-Gravimetric Analysis revealed that the weave pattern and composite thickness had an effect on the rate of weight loss and sustenance until 450 °C. The pattern had an effect on the glass transition temperature, as seen by Differential Scanning Calorimetry. The weave pattern and size thickness had an effect on energy storage and dissipation, displaying the damping behavior in DMA. The weave pattern and size had an effect on the rate of water absorption, which saturated after a few hours. The wettability and thickness of composites hampered the burning rate, with 5.4 mm thickness resulting in a 30% decrease. © 2023