Faculty Publications
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Item Synthesis, electrochemical and optical studies of new cyanopyridine based conjugated polymers as potential fluorescent materials(Elsevier Ltd, 2011) Vishnumurthy, K.A.; Sunitha, M.S.; Safakath, K.; Philip, R.; Vasudeva Adhikari, A.V.In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) carrying cyanopyridine in their backbone via Wittig condensation technique. Their structures were well established by FTIR, 1H NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with the onset decomposition temperature around 300-350 °C in nitrogen atmosphere. Further, their electrochemical, linear and third-order non-linear optical properties have been investigated. The polymers showed low electrochemical band gaps in the range of 1.77-1.99 eV and displayed very good fluorescence emission property in various polar solvents. The fluorescence quantum yields of polymers P1-P4 in tetrahydrofuran (THF) were found to be 35, 42, 38 and 34%, respectively. The effective two-photon absorption coefficients (?) for the polymers were determined by Z-Scan technique and were found to be 1.34 × 10 -11, 1.24 × 10-11, 3.04 × 10-11 and 1.85 × 10-11 m/W for polymers P1-P4, respectively. © 2011 Elsevier Ltd. All rights reserved.Item Investigation of the effect of BaTiO3/CoFe2O4 particle arrangement on the static response of magneto-electro-thermo-elastic plates(Elsevier Ltd, 2018) Mahesh, M.; Kattimani, S.In this article, a framework based on finite element (FE) methods is proposed for predicting the influence of spatial arrangement of two phase Barium Titanate (BaTiO3) and Cobalt Ferric Oxide (CoFe2O4) particulate composites on the static response of magneto-electro-thermo-elastic (METE) plates. The coupled material properties such as piezoelectric, piezomagnetic, dielectric, magnetic permeability, thermal expansion and pyro co-efficients vary significantly with the spatial arrangement of BaTiO3/CoFe2O4 particulates. The coupled FE governing equations accounting the effect of particle arrangement is presented by incorporating linear coupled constitutive equations of METE composites. Through the condensation technique, the governing equations of METE plates are solved to obtain direct (thermal displacements, electric and magnetic potentials) and derived quantities (stresses, electric displacements and magnetic flux densities). A special attention has been placed on evaluating the pyro-electric and pyro-magnetic coupling effects for different packing arrangement considered namely, Body Centered Cubic (BCC), Face Centered Cubic (FCC) and Simple Cubic (SC) METE particulate composites. Further, parametric studies are carried out to analyse the influence of boundary conditions and aspect ratio. The present study reveals that the multiphysics response of METE plates changes significantly with the packing arrangements of BaTiO3/CoFe2O4 particulates and geometrical parameters. It is believed that the obtained solutions would provide insights into design aspects of METE structures. © 2017 Elsevier LtdItem Hygrothermal coupling analysis of magneto-electroelastic beams using finite element methods(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Mahesh, M.; Kattimani, S.C.; Joladarashi, S.In this article, the finite element (FE) method has been used to assess the coupled static behavior of hygro-thermo-magneto-electroelastic (HTMEE) beam. Influence of externally applied hygrothermal loads on the direct (displacements, electric and magnetic potentials) and derived quantities (stresses, electric displacement and magnetic flux densities) of HTMEE beam have been studied in detail. The principle of total potential energy and the coupled constitutive equations of HTMEE material are used for the FE formulation. A generalized condensation technique is adopted to solve the global FE equations of motion. Numerical examples are discussed to examine the effect of hygrothermal loads and distinct effect of moisture concentration on the behavior of the beam. Particular emphasis has been placed to analyze the influence of temperature and moisture dependent elastic stiffness coe?cients associated with empirical constants. Considering the independent effect of temperature and moisture on the coupled static responses, the most significant combination of the empirical constants corresponding to temperature dependency and moisture dependency are explored. Extensive computational examples are considered to examine the significant effect of boundary conditions, temperature gradient, moisture concentration gradient and empirical constants on the static behavior of HTMEE beam. It is observed that the static behavior of HTMEE beam is significantly influenced by the hygrothermal loads and empirical constants. The results presented in this article would serve as a benchmark results in design and analysis of HTMEE structures for sensors and actuators applications. © 2018 Taylor & Francis.Item Free vibration analysis of A357 alloy reinforced with dual particle size silicon carbide metal matrix composite plates using finite element method(Polska Akademia Nauk, 2021) Avinash, A.; Mahesh, V.; Prabhu, R.T.; Gowdru Chandrashekarappa, M.G.C.; Bontha, S.In this work, the free vibration behaviour of A357 composite plate reinforced with dual particle size (DPS) (3 wt.% coarse + 3 wt.% fine, 4 wt.% coarse + 2 wt.% fine, and 2 wt.% coarse + 4 wt.% fine) SiC is evaluated using the finite element method. To this end, first-order shear deformation theory (FSDT) has been used. The equations of motion have been derived using Hamilton's principle and the solution has been obtained through condensation technique. A thorough parametric study was conducted to understand the effect of reinforcement size and weight fraction, boundary conditions, aspect ratio and length-to-width ratio of plate geometry on natural frequencies of A357/DPS-SiC composite plates. Results reveal significant influence of all the above variables on natural frequency of the composite plates. In all the cases, A357 composite plate reinforced with 4 wt.% coarse and 2 wt.% fine SiC particles displayed the highest natural frequency owing to its higher elastic and rigidity modulus. Further, the natural frequencies increase with decrease in aspect ratio of the plate geometry. Natural frequency also decreases with increase in the number of free edges. Lastly, increasing the length-to-width ratio drastically improves the natural frequency of the plates. © 2021 Polish Academy of Sciences. All rights reserved.Item On vibration analysis of functionally graded carbon nanotube reinforced magneto-electro-elastic plates with different electro-magnetic conditions using higher order finite element methods(China Ordnance Industry Corporation, 2021) Mahesh, M.; Harursampath, D.; Kattimani, S.This article deals with evaluating the frequency response of functionally graded carbon nanotube reinforced magneto-electro-elastic (FG-CNTMEE) plates subjected to open and closed electro-magnetic circuit conditions. In this regard finite element formulation has been derived. The plate kinematics adjudged via higher order shear deformation theory (HSDT) is considered for evaluation. The equations of motion are obtained with the help of Hamilton's principle and solved using condensation technique. It is found that the convergence and accuracy of the present FE formulation is very good to address the vibration problem of FG-CNTMEE plate. For the first time, frequency response analysis of FG-CNTMEE plates considering the effect of various circuit conditions associated with parameters such as CNT distributions, volume fraction, skew angle, aspect ratio, length-to-thickness ratio and coupling fields has been carried out. The results of this article can serve as benchmark for future development and analysis of smart structures. © 2020 The Authors