Analysis Of Rectangular Laminated Composite Plates

Abstract

This study is concerned with the analysis of plates made of continuous fiber reinforced laminated composite plates. In this study the classical laminated plate theory which is an extension of classical thin plate theory given by Kirchoff, is also included for basic concepts and so some problems of laminated plate has been solved based on constitutive relations. In that, laminated plate is subjected to in-plane force and bending moment at the geometrical mid-plane is analyzed and stresses and strains are calculated for each individual lamina. Specifically the study concerns the behavior of laminated plates including transverse shear deformations, and transverse normal stresses and strains. Two-displacement model based on two different higher order theories have been developed. Based on the constitutive relations some laminates subjected to in-plane bending moments are analyzed for understanding the bending moment-curvature behavior. Two-displacement based finite elements based on above two different higher order theories have been developed. The two different displacement functions have been expanded as straight-forward power series in terms of thickness coordinate and mid-plane variables, resulting in three and six degree of freedom per node. The highest order displacement model under consideration assumes a cubic in-plane strain field, parabolic transverse shear strain field, and a linear transverse normal strain field. Based on the assumed displacements, nine-node Lagrangian isoparametric element stiffness matrices and the corresponding load vectors have been derived. The objective of study is to evaluate the performance of above derived finite elements. The convergence characteristics and accuracy of these finite elements will be established by applying them to specific problems and comparing the results with each other. In this study, the finite elements developed above will be used to study the effects of plate width-to-thickness ratio, material anisotropy, number of layers and errors in the orientation of the fibers in the layer on the response of rectangular symmetrically laminated composite plates subjected to different types of loads.