Browsing by Author "Mahesh, M."

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A 3D finite element static and free vibration analysis of magneto-electro-elastic beam
(Techno Press technop2@chollian.net, 2017) Mahesh, M.; Kattimani, S.C.
In this paper, free vibration and static response of magneto-electro-elastic (MEE) beams has been investigated. To this end, a 3D finite element formulation has been derived by minimization the total potential energy and linear constitutive equation. The coupling between elastic, electric and magnetic fields can have a significant influence on the stiffness and in turn on the static behaviour of MEE beam. Further, different Barium Titanate (BaTiO3) and Cobalt Ferric oxide (CoFe2O4) volume fractions results in indifferent coupled response. Therefore, through the numerical examples the influence of volume fractions and boundary conditions on the natural frequencies of MEE beam is illustrated. The study is extended to evaluate the static response of MEE beam under various forms of mechanical loading. It is seen from the numerical evaluation that the volume fractions, loading and boundary conditions have a significant effect on the structural behaviour of MEE structures. The observations made here may serve as benchmark solutions in the optimum design of MEE structures. © 2017 Techno-Press, Ltd.
A finite element based assessment of static behavior of multiphase magneto-electro-elastic beams under different thermal loading
(Techno-Press, 2017) Mahesh, M.; Kattimani, S.C.
In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications. © 2017 Techno-Press, Ltd.
A novel receptive field-regularized V-net and nodule classification network for lung nodule detection
(John Wiley and Sons Inc, 2022) Dodia, S.; Annappa, B.; Mahesh, M.
Recent advancements in deep learning have achieved great success in building a reliable computer-aided diagnosis (CAD) system. In this work, a novel deep-learning architecture, named receptive field regularized V-net (RFR V-Net), is proposed for detecting lung cancer nodules with reduced false positives (FP). The method uses a receptive regularization on the encoder block's convolution and deconvolution layer of the decoder block in the V-Net model. Further, nodule classification is performed using a new combination of SqueezeNet and ResNet, named nodule classification network (NCNet). Postprocessing image enhancement is performed on the 2D slice by increasing the image's intensity by adding pseudo-color or fluorescence contrast. The proposed RFR V-Net resulted in dice similarity coefficient of 95.01% and intersection over union of 0.83, respectively. The proposed NCNet achieved the sensitivity of 98.38% and FPs/Scan of 2.3 for 3D representations. The proposed NCNet resulted in considerable improvements over existing CAD systems. © 2021 Wiley Periodicals LLC.
Behaviour of Natural Rubber in Comparison with Structural Steel, Aluminium and Glass Epoxy Composite under Low Velocity Impact Loading
(Elsevier Ltd, 2017) Mahesh, M.; Joladarashi, S.; Kulkarni, S.M.
This paper presents the low velocity gravity impact behaviour of various materials (Structural steel, Aluminium, Rubber and Glass Epoxy composite). A comparison of the above said materials is reported considering various parameters such as Total Energy, contact force, deformation, von mises stress and strain and specific energy absorbed are carried out. The results confirmed that rubber absorbs more energy compared to other materials considered thus highlighting its potential use in structural applications subjected to low velocity impact. The natural rubber in many ways is an ideal polymer for dynamic or static engineering applications. It has excellent dynamic properties, with a low hysteresis loss, and good low temperature properties, it can be bonded well to metal parts, has high resistance to tear and abrasion and it is relatively easy to process. Natural rubber composites find technological interest in that they exhibit additional features like biodegradability and renewability, along with the inherent stiffness, low cost and low density. The great advantage of natural rubber based on its linear elasticity, high strength, fatigue life and excellent adhesion to metals makes it well suited for structural or semi structural applications. Â© 2017 Elsevier Ltd.
Effect of BaTiO3/CoFe2O4 micro-topological textures on the coupled static behaviour of magneto-electro-thermo-elastic beams in different thermal environment
(Institute of Physics Publishing helen.craven@iop.org, 2018) Mahesh, M.; Kattimani, S.C.; Loja, M.A.R.; Mahesh, V.
The use of composite materials with multifunctional capabilities is an increasing requirement for structures or components where the sensory function is accompanied by the diagnosis and the actuation functions, such as autonomic, adaptive or self-sustaining systems. In this context, the present study aims to characterize the coupled response of magneto-electro-thermo-elastic (METE) beams made from Barium Titanate (BaTiO3) and Cobalt Ferric Oxide (CoFe2O4) composite having various micro-topological textures, as well as their static response when submitted to different temperature distribution profiles. To this purpose, a three-dimensional finite element accounting for the coupling between the multiple physical fields in presence, is developed and implemented. The spatial heterogeneous BaTiO3/CoFe2O4 microstructure is also assessed by considering typical Body Centered Cubic (BCC), Face Centered Cubic (FCC) and Simple Cubic (SC) spatial packing arrangements. A special attention is paid to the influence of these micro-topological structures on the pyroeffects and its contribution towards the direct and derived quantities of the METE beam. The results obtained, suggest that the composite heterogeneous microstructure have a relevant influence on the static response of the METE beam in thermal environment. © 2018 IOP Publishing Ltd.
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.
Finite element evaluation of free vibration characteristics of magneto-electro-elastic rectangular plates in hygrothermal environment using higher-order shear deformation theory
(Elsevier Ltd, 2018) Mahesh, M.; Kattimani, S.C.
In this article, the effect of hygrothermal environment on the free vibration characteristics of magneto-electro-elastic (MEE) plates has been studied using finite element method. To this end, higher order shear deformation theory (HSDT) has been employed to assess the displacement fields. Further, using Hamilton's principle and linear coupled constitutive equations of MEE material, the final equilibrium equations for free vibration behaviour of MEE plate in hygrothermal environment has been derived. A special attention has been paid to evaluate the effect of temperature and moisture dependent elastic coefficients on the natural frequencies. The results reveal that the external temperature and moisture fields predominantly affect the stiffness of the plate and hence alter the free vibration characteristics drastically. It is believed that the results presented in this study are useful for the precise design of sensors and actuators in hygrothermal environment. © 2018 Elsevier Ltd
Finite element simulation of controlled frequency response of skew multiphase magneto-electro-elastic plates
(SAGE Publications Ltd info@sagepub.co.uk, 2019) Mahesh, M.; Kattimani, S.
The linear frequency response of skew multiphase magneto-electro-elastic composite plate embedded with active constrained layer damping treatment has been studied. The volume fraction of piezoelectric fibres embedded in the piezomagnetic matrix significantly affects the coupling characteristic of this multiferroic material, and hence, the frequency of the skew multiphase magneto-electro-elastic plate is drastically altered. This study emphasizes on evaluating the influence of different volume fraction of barium titanate (BaTiO3) and cobalt ferrite (CoFe2O4) on the frequency characteristics of skew multiphase magneto-electro-elastic. In this regard, a finite element formulation has been proposed to assess the damped response of such skew multiphase magneto-electro-elastic plates. Incorporating the complex modulus approach, the constrained viscoelastic layer of the active constrained layer damping patch is modelled. In addition, the effect of geometrical skewness has also been investigated. Meanwhile, an exhaustive parametric study is carried out to analyse the influence of control gain, patch position and fibre orientation angle of piezoelectric composite. © The Author(s) 2019.
Finite element simulation of low velocity impact loading on a sandwich composite
(EDP Sciences edps@edpsciences.com, 2018) Mahesh, M.; Joladarashi, S.; Kulkarni, S.M.
Sandwich structure offer more advantage in bringing flexural stiffness and energy absorption capabilities in the application of automobile and aerospace components. This paper presents comparison study and analysis of two types of composite sandwich structures, one having Jute Epoxy skins with rubber core and the other having Glass Epoxy skins with rubber core subjected to low velocity normal impact loading. The behaviour of sandwich structure with various parameters such as energy absorption, peak load developed, deformation and von Mises stress and strain, are analyzed using commercially available analysis software. The results confirm that sandwich composite with jute epoxy skin absorbs approximately 20% more energy than glass epoxy skin. The contact force developed in jute epoxy skin is approximately 2.3 times less when compared to glass epoxy skin. von Mises stress developed is less in case of jute epoxy. The sandwich with jute epoxy skin deforms approximately 1.6 times more than that of same geometry of sandwich with glass epoxy skin. Thus exhibiting its elastic nature and making it potential candidate for low velocity impact application. Â© The Authors, published by EDP Sciences, 2018.
Hygrothermal analysis of magneto-electro-elastic plate using 3D finite element analysis
(Elsevier Ltd, 2017) Mahesh, M.; Kattimani, S.C.
In this article, the static response of magneto-electro-elastic (MEE) plate subjected to hygrothermal loads is investigated using the finite element (FE) method. A FE formulation is derived using the principle of total potential energy and linear coupled constitutive equations of MEE materials by taking into account the thermal and hygroscopic field effects. A uniform temperature rise and moisture concentration rise has been considered. The variations of static parameters are estimated along the MEE plate length by considering the temperature and moisture dependant elastic stiffness coefficients. The coupled FE equilibrium equations in terms of displacements, electric and magnetic potentials are solved directly using condensation procedure. Numerical examples of the FE results are presented and discussed in detail to understand the significant effects of hygrothermal loading, temperature and moisture dependent material properties, boundary conditions and aspect ratio on the direct (displacements, electric potential and magnetic potential) and derived quantities (stresses, electric displacement and magnetic flux density) of MEE plate. © 2017 Elsevier Ltd
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.
Hygrothermal response analysis of MEE beam embedded in adaptive wood through FE methods
(American Institute of Physics Inc. subs@aip.org, 2020) Mahesh, M.; Ravichandra, H.N.; Kattimani, S.C.; Nagaraja, C.V.
The present article evaluates coupled response of magneto-electro-hygrothermo-elastic (MEHTE) beam under framework of finite element methods. Through principle of total potential energy, equations of motions are derived. Solutions are obtained by incorporating the condensation procedure. Credibility of proposed formulation is validated by comparing the outcomes with previously published literature. Results reveal that with higher magnitude of hygrothermal loads, the static parameters of MEHTE beam significantly increases. Further, a comparative study between the thermal load alone and combined hygrothermal load reveals that the moisture effect plays a significant role in coupled response. The present work also attempts to evaluate the effects of various in-plane hygro-thermal loading profiles. Among the various hygrothermal loads considered, uniform hygrothermal load is found to have a predominant effect. Numerical examples are offered to assess individual effect of moisture as well. Â© 2020 Author(s).
Influence of coupled fields on free vibration and static behavior of functionally graded magneto-electro-thermo-elastic plate
(SAGE Publications Ltd info@sagepub.co.uk, 2018) Mahesh, M.; Sagar, P.J.; Kattimani, S.
In this article, the influence of full coupling between thermal, elastic, magnetic, and electric fields on the natural frequency of functionally graded magneto-electro-thermo-elastic plates has been investigated using finite element methods. The contribution of overall coupling effect as well as individual elastic, piezoelectric, piezomagnetic, and thermal phases toward the stiffness of magneto-electro-thermo-elastic plates is evaluated. A finite element formulation is derived using Hamilton’s principle and coupled constitutive equations of magneto-electro-thermo-elastic material. Based on the first-order shear deformation theory, kinematics relations are established and the corresponding finite element model is developed. Furthermore, the static studies of magneto-electro-elastic plate have been carried out by reducing the fully coupled finite element formulation to partially coupled state. Particular attention has been paid to investigate the influence of thermal fields, electric fields, and magnetic fields on the behavior of magneto-electro-elastic plate. In addition, the effect of pyrocoupling on the magneto-electro-elastic plate has also been studied. Furthermore, the effect of geometrical parameters such as aspect ratio, length-to-thickness ratio, stacking sequence, and boundary conditions is studied in detail. The investigation may contribute significantly in enhancing the performance and applicability of functionally graded magneto-electro-thermo-elastic structures in the field of sensors and actuators. © 2017, © The Author(s) 2017.
Influence of Coupled Material Properties of BaTiO3 and CoFe2O4 on the Static Behavior of Thermo-Mechanically Loaded Magneto-Electro-Elastic Beam
(Elsevier Ltd, 2018) Mahesh, M.; Kattimani, S.C.
The present article deals with analyzing the influence of volume fraction (Vf) of Barium Titanate (BaTiO3) and Cobalt-Ferric oxide (CoFe2O4) and its corresponding coupled material properties on the static response of multiphase magneto-electro-elastic (MEE) cantilever beam. Using finite element (FE) methods, the variations of direct and derived quantities across the beam thickness are evaluated. The different volume fractions ranging from Vf =0.0 to Vf =1.0 are considered for analysis. The equilibrium equations are presented with the help of the total potential energy principle and coupled constitutive equations of MEE materials. The numerical results suggest that the displacement components vary accordingly with the volume fraction. In addition, it is found that the maximum electric potential is observed for Vf =0.2 due to pyro-effects, whereas maximum magnetic potential is obtained for Vf =0.0. The numerical study is extended to analyse the layered MEE beam. The influence of stacking sequence and different mechanical load forms on the direct quantities of the beam is evaluated. It is believed that for the precise design of any smart structure, the credibility of the material properties plays a significant role. Hence, in this regard an attempt has been made to understand the behavior of multiphase MEE beams with respect to different volume fractions of Barium titanate (BaTiO3) and Cobalt-Ferric oxide (CoFe2O4). Â© 2017 Elsevier Ltd.
Influence of Ti coated tools on process parameters in turning process of MDN431
(American Institute of Physics Inc. subs@aip.org, 2020) V Badiger, P.V.; Desai, V.; Ramesh, M.R.; Mahesh, M.; Santhosh, C.M.; Prajwala, B.K.; Raveendra, L.
Tungsten carbide tool places in are coated by customized composition of Ti/TiCN/TiN/TiCN/TiN for multilayer and monolayer TiC-C using PVD assisted CAE technique. Quality physiognomies of coatings are evaluated using VDI3198 and Calo tests. Thickness of the coatings for Ti-multilayer and monolayer are found to be 1.837 and 1.198 Î¼m respectively and adhesion quality of HF1 attained. Highly alloyed steel MDN431 is used as machining material to evaluate the performance of coatings. The coated tool insert performance has been evaluated at the machining parameters cutting speed in the range of 59-118 m/min, feed rate is 0.062-0.125 mm/rev and depth of cut is ap 0.2-0.4 mm during machining of MDN431 steel. Experiments are conducted based on L27 full factorial design. Cutting forces and surface roughness are analysed using regression analysis. Desirability approach as well as PSO technique is used to optimize the process parameters. Least cutting force and surface roughness are obtained at the condition of Vc-118 m/min, f-0.063 mm/rev, ap-0.2 mm and Vc-59 m/min, f-0.63 mm/rev, ap - 0.2 mm for Ti-multilayer and TiC-C coatings respectively. To augment the capability of predictive regression models and coefficients of determination (COD), ANN modelling has been adopted. Cutting forces and surface roughness are predicted using ANN and mathematical regression models, predicted data follows the experimental data with minimum absolute error. Tool wear was reduced by 65.7% in Ti-multilayer and TiC-C coated tools compared to uncoated tool. Â© 2020 Author(s).
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 Ltd
Modelling and Analysis of Material Behaviour under Normal and Oblique Low Velocity Impact
(Elsevier Ltd, 2018) Mahesh, M.; Joladarashi, S.; Kulkarni, S.M.
The present article deals with analysis of various engineering materials (rubber, steel, aluminum and glass epoxy) under low velocity gravity impact loading normal to the plate as well as at an oblique angle of 20 degrees. Impact damage remains a major concern for structural components; the impact of objects can create internal damage that can significantly reduce their structural strength, because of its complex nature. The investigation of low velocity impact remains an area of interest and has received much attention. Very few research work have been done on the oblique impact behaviour of composites, where most of them concentrates on high-velocity impact conditions. The study on low-velocity oblique impact of composites are scare. Comparison of the above said materials is reported considering various parameters such as total energy, contact force, deformation, von Mises stress and strain and specific energy absorbed. Specific energy absorbed by each material considered are compared both under normal impact and oblique impact and the results confirmed that rubber absorbs 11.72 times more energy than structural steel, 3.24 times more energy than aluminium and 1.8 times more energy than glass epoxy, when subjected to normal impact. In case of oblique impact at 20 degrees rubber absorbs 47.6 times more energy than structural steel, 14 times more energy than aluminium and 8.6 times more energy than glass epoxy. This makes rubber as an ideal polymer for dynamic structural applications subjected to low velocity impact under oblique condition. Â© 2017 Elsevier Ltd.
Multiphysics response of magneto-electro-elastic beams in thermo-mechanical environment
(Techno Press technop2@chollian.net, 2017) Mahesh, M.; Kattimani, S.C.
In this article, the multiphysics response of magneto- electro-elastic (MEE) cantilever beam subjected to thermo-mechanical loading is analysed. The equilibrium equations of the system are obtained with the aid of the principle of total potential energy. The constitutive equations of a MEE material accounting the thermal fields are used for analysis. The corresponding finite element (FE) formulation is derived and model of the beam is generated using an eight noded 3D brick element. The 3D FE formulation developed enables the representation of governing equations in all three axes, achieving accurate results. Also, geometric, constitutive and loading assumptions required to dimensionality reduction can be avoided. Numerical evaluation is performed on the basis of the derived formulation and the influence of various mechanical loading profiles and volume fractions on the direct quantities and stresses is evaluated. In addition, an attempt has been made to compare the individual effect of thermal and mechanical loading with the combined effect. It is believed that the numerical results obtained helps in accurate design and development of sensors and actuators. © 2017 Techno-Press, Ltd.
Nonlinear free vibration and transient responses of porous functionally graded magneto-electro-elastic plates
(Springer Science and Business Media Deutschland GmbH, 2022) Sh, E.L.; Kattimani, S.; Mahesh, M.
The geometrically nonlinear free vibration and transient response of porous functionally graded magneto-electro-elastic (PFG-MEE) plates are studied based on the first-order shear deformation (FSDT) theory, von Karman's nonlinear strain–displacement relations along with modified power law. With Hamilton's theory, the coupled equations of motion are obtained and analyzed by adapting finite element methods (FEM). Moreover, using Newmark's, Picard's, and Newton–Raphson methods, a porous FG-MEE plate's nonlinear and transient response is analyzed using MATLAB software. After validating the present study, the influence of porosity distribution, porosity index, boundary conditions, aspect ratios, and thickness to length ratios on the nonlinear frequency ratio and nonlinear transient response of porous FG-MEE plate is investigated. It is revealed that geometric parameters, porosity index, boundary conditions, and form of porosity distribution significantly influence the nonlinear frequency ratio and nonlinear transient deflections of porous FG-MEE plates. © 2021, Wroclaw University of Science and Technology.
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