Faculty Publications
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Item Mechanical and sliding wear properties of multi-layered laminates from glass fabric/graphite/epoxy composites(Elsevier Ltd, 2013) Shivamurty, B.; Bhat, K.; Anandhan, S.Multi-layered laminates of bi-directionally woven E-glass fabric/epoxy with different loading of graphite particles were made by hand layup followed by compression molding. Tensile and flexural behaviors, impact strength, hardness and density of these laminates were determined. Wear behaviors of these composites were investigated by a pin-on-disc wear test apparatus. Specific wear rates of these composites strongly depend on their filler content and applied normal loads. The hybrid composite containing 3 wt% of graphite exhibits the optimum mechanical and wear performances. A further increase in the graphite content increases the specific wear rate and deteriorates the mechanical behavior. The lowest (? e)-1 factor (the reciprocal of the product of tensile strength and elongation at break) signifies the lowest specific wear rate. The results of the morphology study of the wear test specimens support the results of the wear test. © 2012 Elsevier Ltd.Item Micro and nanoindentation analysis of porous anodic alumina prepared in oxalic and sulphuric acid(Elsevier Ltd, 2016) Ramana Reddy, P.R.; Ajith, K.M.; Udayashankar, N.K.In this article, the mechanical behavior of porous anodic alumina (PAA) structures obtained from two different electrolytes (oxalic and sulphuric acids) was investigated using micro and nanoindentation techniques. Regularity ratio (RR) of PAA structures was calculated using WSxM software and it was found that strength of the PAA structures varies with the RR of the pores. Micro hardness of the PAA structures was studied using 0.98, 9.8 N loads and it was observed that surface ring cracks were generated for 9.8 N load in oxalic acid. PAA structures formed in sulphuric acid exhibits an extremely high hardness of 7.5 GPa and Young's modulus as 146.5 GPa compared with oxalic acid due to low porosity. Results indicate that the indentation modulus and hardness of the PAA structures decrease with increasing pore size. Further the effect of porosity and regularity ratio of pores on mechanical properties of PAA structures was studied in detail. © 2016 Elsevier Ltd and Techna Group S.r.l.Item Effect of cooling rate on joint shear strength of Sn-9Zn lead-free solder alloy reflowed on copper substrate(ASTM International, 2017) Tikale, S.; Sona, M.; Prabhu, K.Reliability of the solder joint largely depends on mechanical strength, fatigue resistance, coefficient of thermal expansion, and intermetallic compound formation. Cooling rate significantly affects the physical properties of an alloy and influences the mechanical behavior of solder joints. In the present study, Sn-9Zn lead-free solder alloy was solidified on Cu substrate under furnace cooling (0.04°C/s), air cooling (0.16°C/s), and water cooling (94°C/s) conditions. The effect of varying cooling rates on the intermetallic compound (IMC) formation at the interface and the resulting joint shear strength was studied. A microstructure study revealed the presence of Cu5Zn8 and CuZn5 intermetallic compounds at the solder-substrate interface. The IMC layer thickness at the interface increased with a decrease in the cooling rate. The joint shear strength increased with an increase in the cooling rate. The air and furnace cooling resulted in the formation of a thick IMC layer. The IMC obtained from the furnace cooling was associated with micro-cracks leading to a decrease in the joint shear strength. © Copyright 2017 by ASTM International.Item Parametric studies on bending stiffness and damping ratio of Sandwich structures(Elsevier B.V., 2018) Rajpal, R.; Lijesh, L.; Gangadharan, K.V.Sandwich structures are extensively used in aviation industries to reduce the overall weight of the system. Although the mechanical behavior of these structures has been widely studied, the performance of core shape in vibration response has been minimally explored. This study focuses on understanding the various influences of sandwich structures considering the following parameters: (i) nature of core shape, (ii) number of infill shapes, and (iii) orientation of cores, which affect the dynamic behavior of sandwich structures. Nine sandwich structures comprising three different core shapes, hexagon, triangle, and square shapes, in three different orientations, namely 0° 45° and 90° were considered for the present study. These structures in the beginning were put by modal analysis using finite element method (FEM). All the nine structures were printed using the fused deposition method to validate the FEM findings, while the DEWE soft data acquisition system was used to estimate the modal parameters (i) natural frequency and (ii) damping ratio. Natural frequency and damping ratio were estimated using FRF and Nyquist circle plot, respectively. This study demonstrates that although the square core orientated at 0° exhibited superior stiffness in bending loads, the hexagonal core orientated at 0° displayed an admirable combination of both stiffness and damping properties. © 2018 Elsevier B.V.Item Assessment of Cohesive Parameters Using High Dimensional Model Representation for Mixed Mode Cohesive Zone Model(Elsevier Ltd, 2019) Rao, B.; Balu, A.S.Simulation of the mechanical behavior of bonded joints using a cohesive zone model (CZM) is the most common technique to characterize the delamination process. It is usually dependent on the calculation of cohesive parameters of the traction-separation law, and the parameters are iteratively obtained with the help of simulation and experimental results. The non-availability of standard methods to obtain the parameters necessitates the iterative adjustments of simulation results to the experimental results. However, the calculations based on all individuals for the simulation are not effective as it demands high computational effort. To overcome this issue, this paper proposes a computationally efficient method using high dimensional model representation (HDMR). The cohesive parameters are determined by adopting an efficient sampling scheme within the limits of the parameters. Single leg bending (SLB) joint is tested under the influence of dominant conditions such as mode-I and mode-II to determine the equivalent parameters. The errors resulted from the comparison between the simulation, and experimental values are minimized in order to determine the optimal values. The mixed mode (MM) CZM is then established by pure mode cohesive parameters, and the same is implemented to the SLB joint under various mode mixities for analyzing the fracture process. Comparison between the numerical analysis and the experimental study proves that the proposed HDMR based approach estimates the failure mechanism exactly. © 2019 Institution of Structural EngineersItem Ductility and Flame Retardancy Enhancement of PVC by Nanostructured Fly Ash(Springer editorial@springerplus.com, 2019) Patil, A.G.; Mahendran, A.; SelvaKumar, M.; Anandhan, S.Fly ash (FA) obtained from a coal-fired local thermal power station was converted into a nanostructured material by mechano-chemical activation using a high energy planetary ball mill. Contact angle measurements and FTIR spectroscopy confirmed the surface modification of mechano-chemically activated FA (MCA-FA). Subsequently, a solution casting method was used to prepare poly(vinyl chloride) (PVC) matrix composites with varying amounts of fresh FA and MCA-FA. Mechanical testing results of the composites revealed that incorporation of fresh FA in PVC resulted in a higher tensile strength with brittle failure; addition of MCA-FA to PVC resulted in higher elongation at break values while retaining the ductility of the PVC. We have proposed a plausible mechanism explaining the influence of fresh FA and MCA-FA on the mechanical behavior of these composites. As fresh FA and MCA-FA contain basic oxide materials, they tend to improve the fire retardancy of PVC even at a very small loading. Overall, the nanostructured MCA-FA could find application as a filler in PVC-based products. © 2016, Springer Science+Business Media Dordrecht.Item Mechanical behavior of additively manufactured nanoclay/HDPE nanocomposites(Elsevier Ltd, 2020) Beesetty, P.; Kale, A.; Patil, B.; Doddamani, M.Nanoclay (NC) has blended with relatively inexpensive, widely consumed HDPE (high density polyethylene) for the development of filament to be used in 3D printers. NC/HDPE blends are prepared by varying NC wt. % (0.5, 1, 2, and 5) and are subjected to melt flow index (MFI) measurements. MFI has noted to be decreasing with NC loadings. NC/HDPE nanocomposite blends are further extruded using a single screw extruder. Developed nanocomposites filaments are fed to the fused filament fabrication (FFF) based 3D printer for realizing NC/HDPE nanocomposite prints. The density of printed sample increases with filler content. Filament and printed samples thermal study is carried out using differential scanning calorimeter (DSC). NC addition increases crystallinity and crystallization temperature without significant change in melting peak temperature. Freeze fractured prints reveal the uniform distribution of NC in HDPE. The tensile test is conducted on the filaments and prints. Further printed nanocomposites are subjected to flexural investigations. Tensile modulus and strength of filament increase with NC additions in HDPE matrix. Tensile and flexural properties (modulus and strength) of the nanocomposite prints increases with NC content. Finally, results obtained from the tensile and flexural tests of prints are compared with different HDPE composites available in the literature. © 2020 Elsevier LtdItem Role of alloying additions on phase transformations, mechanical and pseudoelastic behavior of Cu-Al-Be shape memory alloys(Elsevier Ltd, 2022) Kalinga, T.; Bala Narasimha, G.; Murigendrappa, S.M.; Kattimani, S.In this study, the influence of alloying additions on phase transformations, microstructure, transformation temperatures, mechanical properties, and pseudoelastic behavior of polycrystalline Cu-Al-Be shape memory alloy has been investigated. Four different SMAs were prepared in the range of 11.0–11.8 wt.% of aluminum and 0.5–0.6 wt.% of beryllium. Results reveal that the alloying of Al ≥ 11.5 wt.% and Be ≥ 0.57 wt.% forms austenite β1(DO3) at room temperature. An increase in both aluminum and beryllium decreases the transformation temperatures, and Cu-11.5Al-0.57Be SMA exhibits smaller energy differences (ΔH) between austenite and martensite. Alloying aluminum and beryllium didn't exhibit significant improvement in mechanical properties due to the existence of coarse grains. Maximum pseudoelasticity of 4% was achieved in Cu-11.5Al-0.57Be SMA with a retained strain of 0.192%. © 2021Item Physico-mechanical behavior of carbon black-infused polymer composite(Springer, 2022) Hiremath, H.; Rajole, S.; Sondar, P.R.; Mathias, K.A.; Kulkarni, S.M.This article deals with the development of polymer composites by incorporating carbon blacks (CBs) into polydimethylsiloxane (PDMS) matrix material for improving the mechanical and physical properties of the polymer composites. CBs of nano-size were used as filler material in varying volume percentages (5–25%), and the polymer composite was processed by solution casting method. Density, elastic modulus and hardness were measured in order to study the effect of the CB-reinforced PDMS matrix. Experimentally obtained mechanical properties were then compared with the standard empirical model. Density of the polymer composite was increased by five times as compared to the pure polymer material. With the increase in volume percentage of CB, both hardness and elastic modulus of the polymer composites were enhanced. Scanning electron microscope images of the composite material showed uniform distribution of CBs, implying strong binding with the matrix material, which attributed to improved mechanical properties. © 2021, Indian Academy of Sciences.Item Incorporation of Sugarcane Bagasse Ash to investigate the mechanical behavior of Stone Mastic Asphalt(Elsevier Ltd, 2022) Akarsh, P.K.; Ganesh, G.O.; Marathe, S.; Rai, R.Stone Mastic Asphalt (SMA) is one kind of new generation gap graded hot mix asphalt with higher content of asphalt with coarse aggregate proportions. The stone-on-stone interlock in SMA makes it superior rut resistant mix and favorable in adverse conditions. The usage of conventional fillers in SMA will lead to the creation of many environmental nuisances and entail additional cost during the production. The use of industrial by-products in the place of the conventional filler can be proven favorable to overcome enhanced production cost of SMA. In the present research work, one such largely produced industrial waste called, Sugarcane Bagasse Ash (SBA) is used as a filler in SMA by replacing conventional Ordinary Portland Cement (OPC) filler, and the engineering performances and cost effectiveness is examined. The SMA mixes were cast with 6.25% optimum binder content are varied with SBA of 2.5% (ACS1), 5.0% (ACS2), 7.5% (ACS3) and 10% (ACS4) by weight of the mix as filler and the results were compared with conventional SMA mix (ACS0). The results showed that, the inclusion of SBA demonstrated superior performances indicating the enhanced stiffness of mix (in terms of Marshall and flow characteristics). Moisture resistance of the SMA mix was improved up to 7.5% SBA replacement. Further, the drain-down test results revealed that, SBA can be effectively used as stabilizing agent. The mix ACS 1 and ACS2 shown a minimum rut depth in reference with ACS0. The mix with 5% SBA resists more number of repetitive loads than all the mix tested. © 2022 Elsevier Ltd