Showing papers by "M. Ganapathi published in 2003"
TL;DR: In this paper, the axisymmetric dynamic behavior of clamped laminated angle-ply composite spherical caps under suddenly applied loads of infinite duration is studied, and the formulation is based on first-order shear deformation theory and it includes the inplane and rotary inertia effects.
24 citations
TL;DR: In this article, the free vibrations and transient dynamic response analyses of laminated cross-ply oval cylindrical shells are carried out based on higher-order theory that accounts for the transverse shear and transverse normal deformations, and includes zig-zag variation in the inplane displacements across the thickness of the multi-layered shells.
21 citations
TL;DR: In this article, the large amplitude free flexural vibrations of isotropic/laminated orthotropic rings are investigated, using a shear flexible curved beam element based on field consistency principle.
Abstract: Here, the large amplitude free flexural vibrations of isotropic/laminated orthotropic rings are investigated, using a shear flexible curved beam element based on field consistency principle. A laminated refined beam theory is introduced for developing the element, which satisfies the interface transverse shear stress and displacement continuity, and has a vanishing shear stress on the inner and outer surfaces of the beam. The formulation includes in-plane and rotary inertia effects, and the non-linearity due to the finite deformation of the ring. The governing equations obtained using Lagrange's equations of motion are solved through the direct integration technique. Amplitude-frequency relationships evaluated from the dynamic response history are examined. Detailed numerical results are presented considering various parameters such as radius-to-thickness ratio, circumferential wave number and ovality for isotropic and laminated orthotropic rings. The nature and degree of the participation of various modes in non-linear asymmetric vibration of oval ring brought out through the present study are useful for accurate modelling of the closed non-circular structures.
20 citations
TL;DR: In this article, the free vibration characteristics of thick laminated composite non-circular cylindrical shells are analyzed using higher-order theory, and the analysis is made to highlight the influences of length and thickness ratios, eccentricity parameters, ply-angles and number of layers on the free vibrational characteristics of noncircular shells.
19 citations
TL;DR: In this article, the elastic buckling characteristics of laminated cross-ply elliptical cylindrical shells under axial compression was studied through finite element approach, and the governing equations obtained using the principle of minimum potential energy were solved through eigenvalue approach.
16 citations
TL;DR: In this paper, the free-vibration behavior of anisotropic laminated angle-ply noncircular cylindrical shells using finite element approach is analyzed based on first-order shear deformation theory.
Abstract: This paper deals with the free-vibration behaviour of anisotropic laminated angle-ply noncircular cylindrical shells using finite element approach. The formulation is based on first-order shear deformation theory. The present model accounts for in-plane and rotary inertia effects. A detailed study has been carried out to highlight the effects of shell geometry, cross-sectional properties, lay-up and ply-angles on the natural frequencies of different types of modes of vibration of non-circular elliptical shell structures.
4 citations
TL;DR: In this article, a nonlinear asymmetric dynamic buckling of clamped laminated angle-ply composite spherical shells under suddenly applied pressure loads is considered, where the buckling loads are obtained through dynamic response history using Newmark's numerical integration scheme coupled with a Newton-Raphson iteration technique.
Abstract: This paper deals with nonlinear asymmetric dynamic buckling of clamped laminated angle-ply composite spherical shells under suddenly applied pressure loads. The formulation is based on first-order shear deformation theory and Lagrange`s equation of motion. The nonlinearity due to finite deformation of the shell considering von Karman`s assumptions is included in the formulation. The buckling loads are obtained through dynamic response history using Newmark`s numerical integration scheme coupled with a Newton-Raphson iteration technique. An axisymmetric curved shell element is used to investigate the dynamic characteristics of the spherical caps. The pressure value beyond which the maximum average displacement response shows significant growth rate in the time history of the shell structure is considered as critical dynamic load. Detailed numerical results are presented to highlight the influence of ply-angle, shell geometric parameter and asymmetric mode on the critical load of spherical caps.
4 citations
Abstract: In this article, the nonlinear free vibration characteristics of isotropic oval rings are analyzed using a shear flexible cubic B-spline curved beam element. The amplitude-frequency relationships are estimated from the response history. the participation of various modes in the total response is highlighted.
3 citations
TL;DR: In this paper, the authors studied the nonlinear dynamic behavior of clamped isotropic/laminated composite spherical caps under suddenly applied load, using a Newmark integration technique coupled with a modie edNewton-Raphsoniteration scheme.
Abstract: Here, the nonlinear dynamic behavior of clamped isotropic/laminated composite spherical caps under suddenly appliedloadsisstudiedusingathree-nodedaxisymmetriccurvedshellelementbasedone eldconsistencyapproach. The formulation is based on e rst-order shear deformation theory, and it includes the in-plane and rotary inertia effects.Geometricnonlinearity is introduced in theformulationusing von Karman’ sstrain-displacementrelations. The governing equations obtained are solved employing the Newmark’ s integration technique coupled with a modie edNewton‐ Raphsoniteration scheme.Theload beyond which themaximum averagedisplacementresponse shows signie cant growth in the time history of the shell structure is taken as dynamic buckling pressure. The present model is validated against theavailableanalytical solutions and also with the results evaluated using threedimensional e nite element method. A detailed parametric study is carried out to bring out the effects of shell geometries, orthotropicity, and the number of layers in the cross-ply laminates on the axisymmetric/asymmetric dynamic buckling load of shallow spherical shells. I. Introduction T HIN spherical shells form an important class of structural components, with many signie cant applications in engineering e elds. These shells subjected to dynamic load could encounter dee ections of the order of the thickness of the shell. The dynamic response of such shells can lead to the phenomenon of dynamic snapping or dynamic buckling. Because these kinds of responses cannot be determined accurately using small displacement theory, nonlinear dynamic analysis is required, and such study has received considerable attention in the literature. However, most of the available works are related to axisymmetric behavior of homogeneous, isotropic, or single-layered orthotropic spherical shells subjected to the step pressure load of ine nite duration. The present tendency to use e ber-reinforced composite materials for the structural components necessitates the analysis of shells made up of layers of such materials, leading to anisotropic behavior. Moreover, quite often, the asymmetric modes of these shells might be excited as a result of the introduction ofslight deviation in perfectaxisymmetric loading, geometric imperfection, and/or initial displacement/velocity to the shells. The anisotropic material properties coupled with the asymmetric structural behavior render the failure analysis of these shells quite complex. Hence, there is a growing appreciation of the importance of studying the dynamic response, in particular, dynamic bucklingoflaminatedcompositesphericalshellsandhasconstituted a major e eld of research in structural mechanics. First, a brief review of important contributions to the axisymmetric dynamic snap-through buckling of spherical case is presented here. The analysis of isotropic shallow spherical shells has been carried out by Budiansky and Roth, 1 Simitses, 2 Huang, 3 Stephens andFulton, 4 BallandBurt, 5 andStricklinandMartinez. 6 Budiansky and Roth 1 have employed the Galerkin method, whereas Simitses 2 adoptedtheRitz ‐Galerkinprocedure.Ae nitedifferenceschemehas been introduced in the method of solution by Huang, 3 Stephens and Fulton, 4 andBallandBurt, 5 whereasStricklinandMartinez 6 utilized
2 citations