Faculty Publications

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Author: search.filters.author.Kattimani, S.Subject: search.filters.subject.First-order shear deformation theory

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    Buckling analysis of skew magneto-electro-elastic plates under in-plane loading
    (SAGE Publications Ltd info@sagepub.co.uk, 2018) Kiran, M.C.; Kattimani, S.
    This article deals with the study of buckling behaviour of multilayered skew magneto-electro-elastic plate under uniaxial and biaxial in-plane loadings. The skew edges of the skew magneto-electro-elastic plate are obtained by transforming the local skew coordinate to the global using a transformation matrix. The displacement fields corresponding to the first-order shear deformation theory along with constitutive equations of magneto-electro-elastic materials are used to develop a finite element model. The finite element model encompasses the coupling between electric, magnetic and elastic fields. The in-plane stress distribution within the skew magneto-electro-elastic plate due to the enacted force is considered to be equivalent to the applied in-plane compressive loads in the pre-buckling range. This stress distribution is used to derive the potential energy functional of the skew magneto-electro-elastic plate. The non-dimensional critical buckling load is attained from the solution of the allied linear eigenvalue problem. Influence of skew angle, stacking sequence, span-to-thickness ratio, aspect ratio and boundary condition on the critical buckling load and their corresponding mode shapes is investigated. © 2018, © The Author(s) 2018.
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    Neural network-based prediction model to investigate the influence of temperature and moisture on vibration characteristics of skew laminated composite sandwich plates
    (MDPI AG, 2021) Kallannavar, V.; Kattimani, S.; Soudagar, M.E.M.; Abbas, M.A.; Alshahrani, S.; Imran, M.
    The present study deals with the development of a prediction model to investigate the impact of temperature and moisture on the vibration response of a skew laminated composite sandwich (LCS) plate using the artificial neural network (ANN) technique. Firstly, a finite element model is generated to incorporate the hygro-elastic and thermo-elastic characteristics of the LCS plate using first-order shear deformation theory (FSDT). Graphite-epoxy composite laminates are used as the face sheets, and DYAD606 viscoelastic material is used as the core material. Non-linear strain-displacement relations are used to generate the initial stiffness matrix in order to represent the stiffness generated from the uniformly varying temperature and moisture concentrations. The mechanical stiffness matrix is derived using linear strain-displacement associations. Then the results obtained from the numerical model are used to train the ANN. About 11,520 data points were collected from the numerical analysis and were used to train the network using the Levenberg– Marquardt algorithm. The developed ANN model is used to study the influence of various process parameters on the frequency response of the system, and the outcomes are compared with the results obtained from the numerical model. Several numerical examples are presented and conferred to comprehend the influence of temperature and moisture on the LCS plates. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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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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    Nonlinear analysis of two-directional functionally graded doubly curved panels with porosities
    (Techno-Press, 2022) Naveen Kumar, H.S.; Kattimani, S.
    This article investigates the nonlinear behavior of two-directional functionally graded materials (TDFGM) doubly curved panels with porosities for the first time. An improved and effectual approach is established based on the improved first-order shear deformation shell theory (IFSDST) and von Karman’s type nonlinearity. The IFSDST considers the effects of shear deformation without the need for a shear correction factor. The composition of TDFGM constitutes four different materials, and the modified power-law function is employed to vary the material properties continuously in both thickness and longitudinal directions. A nonlinear finite element method in conjunction with Hamilton’s principle is used to obtain the governing equations. Then, the direct iterative method is incorporated to accomplish the numerical results using the frequency-amplitude, nonlinear central deflection relations. Finally, the influence of volume fraction grading indices, porosity distributions, porosity volume, curvature ratio, thickness ratio, and aspect ratio provides a thorough insight into the linear and nonlinear responses of the porous curved panels. Meanwhile, this study emphasizes the influence of the volume fraction gradation profiles in conjunction with the various material and geometrical parameters on the linear frequency, nonlinear frequency, and deflection of the TDFGM porous shells. The numerical analysis reveals that the frequencies and nonlinear deformations can be significantly regulated by changing the volume fraction gradation profiles in a specified direction with an appropriate combination of materials. Hence, TDFGM panels can overcome the drawbacks of the functionally graded materials with a gradation of properties in a single direction. © © 2022 Techno-Press, Ltd.
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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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    Frequency response analysis of edge-cracked magneto-electro-elastic functionally graded plates using extended finite element method
    (Elsevier B.V., 2022) Sh, E.L.; Kattimani, S.; Thoi Trung, N.
    This paper studies the frequency response of edge-cracked magneto-electro elastic functionally graded (ECMEE-FG) plates using the extended finite element method (XFEM). First-order shear deformation theory (FSDT), von Karman's nonlinear strain-displacement equations, and a modified power-law are used to develop the numerical model. The coupled equations are derived and analyzed using Hamilton's principle and extended finite element methods. The influence of B-rich bottom and F-rich bottom material gradation, crack orientation, crack length, and aspect ratio on the geometrically nonlinear frequency response was investigated after the current study was validated. Furthermore, crack propagation behavior in the ECMEE-FG plate was examined. The results could be helpful for the design of functionally graded magneto electro elastic structures and devices. © 2022 Elsevier Ltd