Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Kattimani, S.Subject: search.filters.subject.Shear flow

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Now showing 1 - 7 of 7
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    Effect of temperature on the performance of active constrained layer damping of skew sandwich plate with CNT reinforced composite core
    (Taylor and Francis Ltd., 2022) Kallannavar, V.; Kattimani, S.
    In this paper, the first attempt has been made to investigate the performance of the active constrained layer damping system in the thermal environment. For such investigation, a skew laminated composite sandwich plate with carbon nanotube-reinforced composite core is considered. The nonlinear strain-displacement relations are employed to generate the initial-stress stiffness matrix and the mechanical stiffness matrices using linear strain-displacement relations. The negative velocity feedback control-law is used to control the first few modes of the vibrating sandwich plate. Comprehensive investigation has been carried out to understand influence of geometric and material parameters on the damping performance of the system. © 2021 Taylor & Francis Group, LLC.
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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 porosity on active damping of geometrically nonlinear vibrations of a functionally graded magneto-electro-elastic plate
    (China Ordnance Industry Corporation, 2022) Esayas, L.S.; Kattimani, S.
    This paper investigates the effect of porosity on active damping of geometrically nonlinear vibrations (GNLV) of the magneto-electro-elastic (MEE) functionally graded (FG) plates incorporated with active treatment constricted layer damping (ATCLD) patches. The perpendicularly/slanted reinforced 1–3 piezoelectric composite (1–3 PZC) constricting layer. The constricted viscoelastic layer of the ATCLD is modeled in the time-domain using Golla-Hughes-McTavish (GHM) technique. Different types of porosity distribution in the porous magneto-electro-elastic functionally graded PMEE-FG plate graded in the thickness direction. Considering the coupling effects among elasticity, electrical, and magnetic fields, a three-dimensional finite element (FE) model for the smart PMEE-FG plate is obtained by incorporating the theory of layer-wise shear deformation. The geometric nonlinearity adopts the von Kármán principle. The study presents the effects of a variant of a power-law index, porosity index, the material gradation, three types of porosity distribution, boundary conditions, and the piezoelectric fiber's orientation angle on the control of GNLV of the PMEE-FG plates. The results reveal that the FG substrate layers' porosity significantly impacts the nonlinear behavior and damping performance of the PMEE-FG plates. © 2021 China Ordnance Society
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    Static, buckling, and free vibration characteristics of porous skew partially functionally graded magneto-electro-elastic plate
    (Taylor and Francis Ltd., 2023) Kiran, K.; Wang, W.; Fang, C.; Kattimani, S.
    In this article, a new mathematical model to develop porous skew partially functionally graded (SPFG) magneto-electro-elastic (MEE) plate from a stepped functionally grade (SFG) plate is proposed. The combination of Barium Titanate (BaTiO3) and Cobalt Ferrite (CoFe2O4) is graded stepwise to achieve SFG plates. Such, SFG plate is approximated using modified power law for functional variation through its thickness. Modified first-order shear deformation theory (FSDT) is deployed in the current study to develop mathematical models. The geometrical modification from rectangular to skew plate is achieved using transformation matrix. Porosity in the partial functionally graded MEE plate is taken as local density. Free vibration study is carried out to reflect the influence of partial gradation, porosity distribution, porosity volume, and skew angle on the natural frequency of porous SPFG MEE plate. The influence of various types of porosity distribution, partial gradation, and skew angle on the primary quantities such as displacements, potentials, and secondary quantities such as stresses, electric displacement, and magnetic induction on SPFG MEE plate is studied. The stability characteristics of the SPFG MEE plate are also investigated to study the buckling behavior under various porosity distributions, partial gradation, and skew angles. The effect of change in aspect ratio, and thickness ratio on the free vibration and static behavior is also investigated. © 2021 Taylor & Francis Group, LLC.
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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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    Influence of hybrid smart damping system on bi-directionally tapered functionally graded plate using 1-3 PZC resting on winkler-pasternak flexible support
    (SAGE Publications Inc., 2025) Shada, S.K.; Kattimani, S.; Ramesh, M.R.
    This article presents a numerical investigation of free vibrational features of bi-directionally tapered functionally graded (BTFG) plate unified with active constrained layer damping (ACLD) on a two-parameter Winkler-Pasternak flexible support. In conjunction with the virtual work principle, the first-order shear theory for deformation is employed. The plate’s damping is actively controlled using a velocity feedback control system with 1-3 piezoelectric patches consisting of piezoelectric and viscoelastic layers. Effects of foundation/support parameters (Kw and Ks), taper ratios, ACLD patch placement, and boundary conditions are systematically analysed through frequency response studies. Results demonstrate that incorporating ACLD patches significantly enhances damping features. Revealing with edge patch placement yields superior vibration suppression on the substrate plate. The study highlights the synergistic impact of ACLD patches, flexible supports, and active control, presenting a robust solution for precision vibration control in advanced structural applications. © The Author(s) 2025
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    Non-linear thermal stability and free vibration behavior of sandwich beams with auxetic re-entrant aluminum cores and graphene origami-enhanced facings
    (Elsevier Ltd, 2025) Shashiraj; Pitchaimani, J.; Kattimani, S.
    Revolutionizing advanced sandwich structures, this study delves into the non-linear thermal stability behavior and free vibration characteristics of auxetic aluminum re-entrant core sandwich beams enhanced with graphene origami (GOri) metamaterial facings, subjected to spatially varying thermal environment. The sandwich beams are modeled as layered structures incorporating complex geometric non-linearities, using a higher-order shear deformation framework and non-linear strain–displacement kinematics based on von Kármán assumptions. The governing equations of motion are addressed through the Ritz formulation, enabling an in-depth investigation of how variations in graphene origami layout, concentration, and fold geometry within the face sheets influence the structural performance. Additionally, the influence of various core Poisson's ratio configurations-negative (NPR), zero (ZPR), and positive (PPR)-along with the effects of core angle and thickness ratio, are systematically explored. The results highlight that core topology critically influences post-buckling resistance and non-linear vibrational characteristics. Furthermore, the integration of graphene origami significantly enhances stiffness and structural stability, demonstrating its potential for next-generation aerospace, automotive, and high-performance engineering applications. To the best of the authors’ knowledge, this is the first study to explore the coupled effects of auxetic re-entrant aluminum cores and graphene origami-enhanced facings on the non-linear thermal and dynamic behavior of sandwich beams. © 2025 Elsevier Ltd