Faculty Publications
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Item 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. © 2022Item A comprehensive damping study of variable stiffness composite rectangular/skew laminates reinforcement with curvilinear fibers by higher-order shear flexible model(Taylor and Francis Ltd., 2023) Mohamed, H.; Gunasekaran, V.; Jeyaraj, J.; Vasudevan, V.; Kotriwar, G.; Manickam, G.In this work, a comprehensive investigation of curvilinear fiber reinforcement on damping of rectangular and skew composite plates is computationally estimated using higher-order shear flexible model. A set of governing equilibrium equations developed here in form of eigenvalue analysis is solved by adopting the Q-R algorithm. The damping factors associated with different vibrational modes are evaluated from the complex eigenvalues. The proposed model is validated against the available analytical and experimental results. The damping capability of laminated rectangular/skew composite plates is thoroughly analyzed by varying the curvilinear fiber path angles in the layers, lay-up orientations, structural boundary conditions, skew angle of the laminate, and nature of the material. Results reveal that the damping pretending to the curvilinear fibers plate is better than the conventional composite laminate; it varies significantly according to the variation in center and edge of the curvilinear fiber angles. It is also noted that the damping increases with the skew angle of the plate. The study conducted here shows the suitability of such variable stiffness composite structure for safe design under dynamic/impact loading situation. © 2022 Taylor & Francis Group, LLC.