الفهرس 
Introduction
A refined nonlinear first-order shear deformation zigzag theory of composite laminated platesOnly 14 pages are availabe for public view
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Abstract
The great increase in the use of composite materials in all types of engineering structures motivated the development of more rigorous and general theories of composite laminated structures. The current thesis presents two refined nonlinear firstorder shear deformation theories of composite laminated plates using a modified version of Reissner?s mixed variational principle. This principle has played an increasing role in the field of accurate modeling of multilayered structures. The first theory is an equivalent singlelayer shear deformation theory of geometrically nonlinear composite laminates. The present formulation permits one to assume continuous and smooth displacements varying linearly in the thickness direction, and to introduce a shear and normal stresses satisfying the conditions on the bounding surfaces. Therefore, this theory alleviates some deficiencies of the firstorder shear deformation theories, and it does not need any shear correction factor used in other theories. In addition, this theory is adequate in predicting accurately the global response of the laminate. The second theory is considered as discretelayer model, where it is based on piecewise, layerbylayer displacements and stresses which satisfy both the compatibility conditions (i.e. continuity conditions) at the layer interfaces, and the conditions on the bounding surfaces. Although, the order of governing equations depends on the total number of layers, they are relatively simple for solution. Moreover, this theory is very accurate for both, the local and global responses of the laminated plates. To assess the validity of the present theories, the bending problems of simply supported laminated plates subjected to thermal or mechanical loadings are solved. Comparisons of some present results are made with results of other authors obtained due to exact elasticity solution and approximate higherorder solutions. These comparisons showed that the present theories predict the global and local responses parameters with excellent accuracy, and in general, it is more accurate than any equivalent singlelayer theory. The main results of the present thesis are included in two papers. The first one is published in Journal of Composite Structures. The second paper is submitted in the same journal and it is under reviewing.