Faculty Publications
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Item Vibration analysis of a tapered laminated thick composite plate with ply drop-offs(Springer Verlag service@springer.de, 2015) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, R.; Jeyaraj, J.In this study, vibration characteristics of a tapered laminated thick composite plate have been investigated using finite element method by including the shear deformation and rotary inertia effects. The governing differential equations of motion of a tapered laminated thick composite plate are presented in the finite element formulation based on first-order shear deformation theory for three types of taper configurations. The effectiveness of the developed finite element formulation in identifying the various dynamic properties of a tapered laminated thick composite plate is demonstrated by comparing natural frequencies evaluated using the present FEM with those obtained from the experimental measurements and presented in the available literature. Various parametric studies are also performed to investigate the effect of taper configurations, aspect ratio, taper angle, angle ply orientation and boundary conditions on free and forced vibration responses of the structures. The comparison of the transverse free vibration mode shapes of the uniform and tapered composite plates under various boundary conditions is also presented. The forced vibration response of a composite plate is investigated to study the dynamic response of tapered composite plate under the harmonic force excitation in various tapered configurations. It is concluded that the dynamic properties of laminated thick composite plates could be tailored by dropping off the plies to yield various tapered composite plate. © 2015, Springer-Verlag Berlin Heidelberg.Item Buckling and dynamic characteristics of a laminated cylindrical panel under non-uniform thermal load(Techno Press technop2@chollian.net, 2016) Bhagat, V.; Jeyaraj, J.; Murigendrappa, S.M.Buckling and free vibration behavior of a laminated cylindrical panel exposed to non-uniform thermal load is addressed in the present study. The approach comprises of three portions, in the first portion, heat transfer analysis is carried out to compute the non-uniform temperature fields, whereas second portion consists of static analysis wherein stress fields due to thermal load is obtained, and the last portion consists of buckling and prestressed modal analyzes to capture the critical buckling temperature as well as first five natural frequencies and associated mode shapes. Finite element is used to perform the numerical investigation. The detailed parametric study is carried out to analyze the effect of nature of temperature variation across the panel, laminate sequence and structural boundary constraints on the buckling and free vibration behavior. The relation between the buckling temperature of the panel under uniform temperature field and non-uniform temperature field is established using magnification factor. Among four cases considered in this study for position of heat sources, highest magnification factor is observed at the forefront curved edge of the panel where heat source is placed. It is also observed that thermal buckling strength and buckling mode shapes are highly sensitive to nature of temperature field and the effect is significant for the above-mentioned temperature field. Furthermore, it is also observed that the panel with antisymmetric laminate has better buckling strength. Free vibration frequencies and the associated mode shapes are significantly influenced by the non-uniform temperature variations. © 2016 Techno-Press, Ltd.Item Structural optimization of rotating tapered laminated thick composite plates with ply drop-offs(Springer Netherlands, 2017) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, V.; Jeyaraj, J.In this study, structural optimization of rotating tapered thick laminated composite plates with ply drop-offs has been investigated numerically. The governing differential equations of motion of the tapered composite plate have been presented including the energy associated with the inertia force, coriolis force, displacement dependent centrifugal force and initial stress resultants due to steady state rotation. Four noded quadrilateral finite element has been formulated based on the first order shear deformation theory. Finite element analysis results are validated with experimental results for natural frequencies of the tapered plate with various configurations. Various cases of optimization problems are formulated with different objective functions in terms of maximization of natural frequencies and damping factors (individually and combined) and solved using genetic algorithm in order to obtain optimal ply sequence and ply orientation. It is shown that the optimization problem with maximization of fundamental modal damping factor without rotating condition yields the optimal layout as 90° for all the layers in the plate. It is also observed that maximization of the fundamental modal damping factor yields identical optimal orientation for uniform and all the configurations of a tapered composite plate. © 2015, Springer Science+Business Media Dordrecht.Item Meta-heuristic optimization of buckling and fundamental frequency of laminated cylindrical panel under graded temperature fields(SAGE Publications Ltd, 2021) Bhagat, V.; Jeyaraj, J.This research deals with the optimization of buckling and fundamental frequency of a cylindrical panel under various heating conditions, which varies across the surface of the panel. A multi-objective design indicator (MODI) is derived with fiber orientations as a design variable. Finite element analysis is used to calculate temperature variation according to the nature of heating, buckling temperature, and fundamental frequency. In this study, scientific computing software is used to incorporate the finite element method with artificial neural network and particle swarm optimization technique. Five different heating cases, including uniform temperature cases, are considered. It is observed from the analysis that the in-plane temperature field of non-uniform type has a significant influence on the buckling and vibration characteristics of the panel. Further, it is observed that panel with lamination scheme of (Formula presented.) gives the higher value of MODI max compared to other lamination schemes considered. © The Author(s) 2020.Item Static stability and free vibration characteristics of a micro laminated beam under varying axial load using modified couple stress theory and Ritz method(Elsevier Ltd, 2022) Priyanka, R.; Jeyaraj, J.This paper explores the buckling and free vibration behaviors of micro laminated composite beams (MLCBs) exposed to varying axial loads using the modified couple stress theory (MCST), with arbitrary boundary conditions and layups. The size effect is captured in MCST by taking into account the material length scale parameters. In the axial direction, the applied load has either constant, linear, or parabolic variations. The equilibrium equations are derived and solved using Hamilton's principle and Ritz method respectively. The size effect is observed to be more pronounced when the thickness of the beam is similar to the material length scale parameter, and it nearly vanishes as the beam thickness increases. The small size effect variation is different for different boundary conditions. For parabolically increasing loading case, the rate of reduction of the fundamental frequency with an increase in applied load intensity is greater compared to other loadings. © 2021 Elsevier LtdItem Nonlinear flutter of 2D variable stiffness curvilinear fibers composite laminates by a higher-order shear flexible beam theory with Poisson's effect(Elsevier Ltd, 2022) Manickam, G.; Vasudevan, V.; Gunasekaran, V.; Jeyaraj, J.; Mohamed, H.In this work, the nonlinear supersonic panel flutter characteristics of two-dimensional variable stiffness curvilinear fibres based laminated composite panels are studied using a higher-order shear flexible theory represented by sine function coupled with first-order approximation leading to quasi-aerodynamic theory. The structural formation takes care of geometric nonlinearity with von Karman's assumptions. The beam constitutive equation is modified for the laminated beam with general lay-up by accounting for Poisson's effect. The nonlinear dynamic equilibrium equations developed by Lagrangian equations of motion are solved using finite element approach in conjunction with the direct iterative solution procedure. For limit cycle oscillation, critical dynamic pressure is predicted iteratively through eigenvalue analysis, thereby identifying the first coalescence of vibrational modes. Also, the flutter behavior of two-dimensional panel under static differential pressure is investigated considering nonlinear static equilibrium position of panel obtained by Newton-Raphson's iterative approach and then followed by modes coalescence approach. These solution procedures are tested against the results in literature. A thorough numerical investigation is done to show the effect of the curvilinear fiber path orientation, limited cycle amplitude, static differential pressure, panel thickness, panel end condition flexibilities and thermal environment on the nonlinear supersonic panel flutter of two-dimensional variable stiffness laminated panels. © 2022