Faculty Publications

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Author: search.filters.author.Kattimani, S.Subject: search.filters.subject.Vibration analysis

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    Free vibration and static analysis of functionally graded skew magneto-electro-elastic plate
    (Techno-Press, 2018) Kiran, M.C.; Kattimani, S.
    This article presents a finite element (FE) model to assess the free vibration and static response of a functionally graded skew magneto-electro-elastic (FGSMEE) plate. Through the thickness material grading of FGSMEE plate is achieved using power law distribution. The coupled constitutive equations along with the total potential energy approach are used to develop the FE model of FGSMEE plate. The transformation matrix is utilized in bringing out the element matrix corresponding to the global axis to a local axis along the skew edges to specify proper boundary conditions. The effect of skew angle on the natural frequency of an FGSMEE plate is analysed. Further, the study includes the evaluation of the static behavior of FGSMEEplate for various skew angles.The influence of skew angle on the primary quantities such as displacements, electric potential, and magnetic potential, and secondary quantities such as stresses, electric displacement and magnetic induction is studied indetail. In addition, the effect of power-law gradient, thickness ratio, boundary conditions and aspect ratio on the free vibration and static response characteristics of FGSMEE plate has been investigated. © 2018 Techno-Press, Ltd.
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    Porosity influence on structural behaviour of skew functionally graded magneto-electro-elastic plate
    (Elsevier Ltd, 2018) Kiran, M.C.; Kattimani, S.; Mahesh, M.
    This article presents a finite element (FE) formulation to assess the influence of porosity on the static responses and free vibration of functionally graded skew magneto-electro-elastic (FGSMEE) plate. The porosity is accounted for local density using modified power law. The skew edges of the plate are achieved by implementing transformation matrix. The coupled constitutive relations establish the different couplings associated with MEE materials. The displacements, potentials, and stresses for the porous skew plate are established through static analysis. The influence of porosity on the natural frequency of the skew plate is investigated via free vibration analysis. The influence of different porosity distributions on various skew angles of the FGSMEE plate has been studied. The effect of porosity volume, skew angle, and geometrical parameters such as aspect ratio, thickness ratio, and boundary conditions on the porous FGSMEE plate is investigated. © 2018 Elsevier Ltd
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    Coupled evaluation of the free vibration characteristics of magneto-electro-elastic skew plates in hygrothermal environment
    (Techno-Press, 2019) Mahesh, V.; Kattimani, S.; Harursampath, D.; Nguyen, N.-T.
    The present article addresses the coupled free vibration problem of skew magneto-electro-elastic plates (SMEE) considering the temperature-moisture dependent material properties. The plate kinematics follows Reddy?s higher order shear deformation theory. With the aid of finite element methods, the governing equations of motion are derived considering the Hamilton?s principle and solved by adopting condensation technique. The influence of different temperature and moisture dependent empirical constants on the frequency response of SMEE plate has been assessed. In addition, the natural frequencies corresponding to various fields are evaluated and the effect of empirical constants on these coupled frequencies is determined. A detailed parametric study has been carried out to assess the individual effects of temperature and moisture dependent empirical constants along with their combined effect, aspect ratio, length-to-width ratio, stacking sequence and boundary conditions. The results reveal that the external environment as well as the geometrical skewness has a significant influence on the stiffness of the SMEE plates. © 2019 Techno-Press, Ltd.
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    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
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    Influence of porosity distribution on nonlinear free vibration and transient responses of porous functionally graded skew plates
    (China Ordnance Industry Corporation, 2021) Kumar H S, N.; Kattimani, S.; Nguyen, T.
    This article deals with the investigation of the effects of porosity distributions on nonlinear free vibration and transient analysis of porous functionally graded skew (PFGS) plates. The effective material properties of the PFGS plates are obtained from the modified power-law equations in which gradation varies through the thickness of the PFGS plate. A nonlinear finite element (FE) formulation for the overall PFGS plate is derived by adopting first-order shear deformation theory (FSDT) in conjunction with von Karman's nonlinear strain displacement relations. The governing equations of the PFGS plate are derived using the principle of virtual work. The direct iterative method and Newmark's integration technique are espoused to solve nonlinear mathematical relations. The influences of the porosity distributions and porosity parameter indices on the nonlinear frequency responses of the PFGS plate for different skew angles are studied in various parameters. The effects of volume fraction grading index and skew angle on the plate's nonlinear dynamic responses for various porosity distributions are illustrated in detail. © 2021 The Authors
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    Effect of different geometrical non-uniformities on nonlinear vibration of porous functionally graded skew plates: A finite element study
    (China Ordnance Industry Corporation, 2022) Kumar H S, H.S.; Kattimani, S.
    This article presents the investigation of nonlinear vibration analysis of tapered porous functionally graded skew (TPFGS) plate considering the effects of geometrical non-uniformities to optimize the thickness in the structural design. The TPFGS plate is analyzed considering linearly, bi-linearly, and exponentially varying thicknesses. The plate's effective material properties are tailor-made using a modified power-law distribution in which gradation varies along the thickness direction of the TPFGS plate. Incorporating the non-linear finite element formulation to develop the kinematic equation's displacement model for the TPFGS plate is based on the first-order shear deformation theory (FSDT) in conjunction with von Karman's nonlinearity. The nonlinear governing equations are established by Hamilton's principle. The direct iterative method is adopted to solve the nonlinear mathematical relations to obtain the nonlinear frequencies. The influence of the porosity distributions and porosity parameter indices on the nonlinear frequency responses of the TPFGS plate for different skew angles and variable thicknesses are studied for various geometrical parameters. The influence of taper ratio, variable thickness, skewness, porosity distributions, gradation, and boundary conditions on the plate's nonlinear vibration is demonstrated. The nonlinear frequency analysis reveals that the geometrical non-uniformities and porosities significantly influence the porous functionally graded plates with varying thickness than the uniform thickness. Besides, exponentially and linearly variable thicknesses can be considered for the thickness optimizations of TPFGS plates in the structural design. © 2021 China Ordnance Society
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    Influence of Temperature and Moisture on Free Vibration Behavior of Skew Laminated Composite Sandwich Panels with CNTRC Core
    (World Scientific, 2022) Kallannavar, V.; Kattimani, S.; Ramesh, H.
    This paper presents the influence of temperature and moisture on the free vibration characteristics of skew laminated composite sandwich (SLCS) panels. The face sheets of the panels are made of graphite-epoxy composite, while the core consists of carbon nanotube-reinforced composite. The coupled hygro-elastic and thermo-elastic relations for the SLCS shells/panels are formulated using first-order shear deformation theory. The nonmechanical stiffness matrices are represented by the initial stress stiffness matrix developed using nonlinear strain-displacement relations. The temperature and moisture-dependent material properties are considered to analyze the laminated composite sandwich spherical, hyperbolic, ellipsoid, cylindrical Shells, and flat plates. Several numerical examples are comprehensively studied to establish the influence of temperature, moisture, the volume fraction of carbon nanotubes in the core material, functional gradation types, skew angle, and edge constraints on the vibration responses of SLCS shells. Further exploration is devoted to studying the combined effect of moisture, temperature, and the geometrical parameters such as length to width ratio, length to thickness ratio, radius-to-length ratio, and the core thickness to face sheet thickness ratios on the natural frequency of the skew laminated composite sandwich panels. © 2022 World Scientific Publishing Company.
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    Effect of temperature and porosity on free vibration characteristics of a doubly-curved skew laminated sandwich composite structures with 3D printed PLA core
    (Elsevier Ltd, 2023) Kallannavar, V.; Kattimani, S.
    This paper deals with the investigation of the influence of temperature and porosity on the vibration response of the doubly-curved skew laminated sandwich composite (DSLSC) shells. The temperature-reliant properties of the graphite–epoxy face sheet and the 3D printed polylactic acid (PLA) core are considered for the numerical analysis. The coupled thermo-elastic finite element (FE) model is developed using the first-order shear deformation theory (FSDT) to study the influence of uniform temperature rise on the modal behavior of the DSLSC shells. The stiffness generated due to thermal exposure is accounted to introduce the initial stress stiffness matrix. Further, the initial stress stiffness matrix is developed using nonlinear strain–displacement relations, while the mechanical stiffness matrices are characterized using linear strain–displacement relations. A comprehensive parametric study has been performed to appreciate the effect of temperature, geometric restraints, and material constraints of a laminated composite sandwich spherical, hyperbolic, ellipsoidal, cylindrical shells, and flat plates. Series of experiments are performed to understand the influence of temperature on the natural frequency of glass–epoxy laminated composite sandwich plates with 3D printed PLA core. Further exploration is dedicated to comprehending the experimental challenges involved in studying the vibration performance of sandwich structures with 3D printed PLA core in the thermal environment. © 2022 Elsevier Ltd
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    Free vibration analysis of a skew sandwich plate with bamboo biocomposite and polylactic acid core under temperature and moisture conditions
    (SAGE Publications Inc., 2023) Gawande, A.S.; Kattimani, S.; Murigendrappa, S.M.; Nguyen, T.; kamyab, H.; Althamer, S.
    This article investigates the impact of moisture and temperature on vibration characteristics of bio-composite skew-laminated composite sandwich (SLCS) plates. The bio-composite SLCS plates with bamboo face sheets and polylactic acid (PLA) cores are biodegradable, radiolucent, lightweight, high strength, and withstand vibrations. The coupled thermo-elastic and hygro-elastic finite element (FE) model of the SLCS plate is derived using the higher-order shear deformation theory (HSDT). An initial stress stiffness matrix is developed using the nonlinear strain-displacement relations to incorporate the effect of temperature and moisture in FE modeling. Temperature and moisture-dependent material properties of bamboo fiber-reinforced biocomposite (BFB) and PLA core are employed for the analysis. A comprehensive investigation has been carried out to study the impact of moisture and temperature situations with different geometrical parameters and various skew angles on the frequency of the SLCS plate. The results indicate that the biocomposite sandwich material has excellent potential for structural applications under different environmental conditions in various applications like food processing, and biomedical applications, including MRI and CT scan beds. © The Author(s) 2023.
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    Nonlinear buckling and free vibration analysis of auxetic graphene origami composite beams under nonuniform thermal environment
    (Taylor and Francis Ltd., 2025) Shashiraj; Pitchaimani, J.; Kattimani, S.
    This study examines the thermo-mechanical behavior of auxetic metamaterial beams enhanced by graphene origami (GOri) under spatially varying nonuniform temperature distributions (SVTD). Utilizing Timoshenko beam theory considering von-Kármánn type nonlinear strain–displacement relationship, GOri beams are modeled as layered structures. The Ritz method is employed to solve equilibrium equations, analyzing the impact of GOri distribution patterns, content, and folding degree on post-buckling and vibration paths. The effects of five SVTDs, three end conditions, and three GOri distribution patterns on buckling, post-buckling behavior, and nonlinear free vibration characteristics are explored. Findings reveal that the parabolic temperature distribution with peak temperatures at beam ends (P-MAE) results in higher critical temperatures and nonlinear free vibration frequencies. This research provides crucial insights into the design and optimization of GOri-enabled metamaterial structures in complex thermal environments, highlighting the significant influence of nonuniform temperature distributions along the beam’s length. © 2024 Taylor & Francis Group, LLC.