Recent developments in finite element analysis for laminated composite plates

Postbuckling of piezoelectric FGM plates subject to thermo-electro-mechanical loading

A review on optimization of composite structures Part I: Laminated composites

Thermal buckling analysis of rectangular composite multilayered plates under uniform temperature rise is investigated using a layerwise plate theory. von Karman strain–displacement equations are employed to account for large deflections occurrence. It is already proven that the layerwise theory results are compatible with the three-dimensional theory of elasticity results. The accuracy of the present results is increased by substituting each layer by many virtual sub-layers. The final governing equations are not simplified or linearized. Material properties are assumed to vary with temperature. Hermitian finite element formulation is used to ensure a C1 continuity for the lateral deflections. No semi-analytic solution is employed to reduce the problem to an eigenvalue one. Layerwise formulations are usually displacement-based. Therefore, force or moment boundary conditions (e.g. simply supported boundary condition), are approximately satisfied. A FEM algorithm is presented to exactly incorporate the boundary conditions. A proposed numerical scheme and a modified Budiansky instability criterion presented by the author are used to determine the buckling temperature in a computerized solution. Finally, results of the present techniques are compared with the results of the high-order theories presented by some well-known researchers and the influences of various geometric and mechanical properties parameters of the composite plate on the buckling temperature are studied.

Thermal buckling analysis of rectangular composite plates with temperature-dependent properties based on a layerwise theory

Finite element analysis of functionally graded plates under transverse load

Thermal postbuckling analysis of laminated composite plates

Buckling temperatures of graphite/epoxy laminated composite plates are maximized for a given total thickness considering fiber-directions and relative thicknesses of layers as design variables. Thermal buckling analysis is carried out using the finite element method with 4 node shear deformable plate element, while genetic algorithm (GA) is employed to optimize as many as ten variables for the five layered plates. In addition to traditional three-operator approach, i.e., reproduction, crossover and mutation, other variants of GAs such as the elitist model, two-point crossover models are also discussed. The study includes composite plates of three different aspect ratios, two support conditions and three different numbers of layers. The presented results reveal that the buckling loads can be increased significantly with appropriately orienting the fiber directions and varying the thickness of different layers. The authors also recommend the judicious selection of specific thicknesses and fiber orientations...

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Optimum Design of Laminated Composite Plates for Maximum Thermal Buckling Loads

The buckling and postbuckling analysis of shear deformable composite skew plates subjected to combined uniaxial compression and uniform temperature rise has been carried out using the finite element method. The governing nonlinear finite element equation is posed as a sequence of linear eigenvalue problems, and each one of them is solved for different amplitudes of deflection to trace the thermal postbuckling path. A maximum strength criterion is used to identify the laminates that have failed in strength, and appropriate modifications are made to the stiffness matrix. The first-ply failure of laminates has also been predicted by Tsai-Hill and Tsai-Wu criteria. Postbuckling paths are traced for different boundary conditions of the plate. Specific numerical studies have been reported showing the effects of skew angle, initial uniaxial compression, and thickness-to-span ratio on the thermal postbuckling behavior of the eight-layered [45/-45/0/90 deg] s symmetric plate. The presence of secondary instability has been identified while tracing the postbuckling path.

J. N. Bandyopadhyay

Papers

Thermal postbuckling analysis of laminated composite plates

Optimum Design of Laminated Composite Plates for Maximum Thermal Buckling Loads

Stability and strength of composite skew plates under thermomechanical loads