Dynamic Finite Element Analysis of Laminated Composite Plates

Abstract

Fibre Reinforced Laminated composites are widely used in Aerospace and Civil Engineering Structures due to its higher strength to weight and stiffness to weight ratio. This paper is concerned with the study of analysis and behaviour of laminated plated made up of continuous fibre reinforced composite materials. In analysis study natural frequencies and mode shapes are calculated using finite element method. Two Displacement models with six and eleven degrees of freedom per node based on Higher Order Shear Deformation Theory (HOSDT) are considered. First displacement model considers transverse displacement, rotations and their higher order terms. While second displacement model is based on inplane and transverse displacements, rotations and their higher order terms. Stiffness matrix and mass matrix of eight - node Quadrilateral isoparametric finite element is derived considering two displacement models. The objective is to study the performance of above derived finite elements in dynamic analysis of laminated composite plate. Free vibration analysis is carried out using finite element method to obtain natural frequencies and corresponding mode shapes with varying width-tothickness ratio, material anisotropy, and number of layers of the fibers with different angle of orientation, support conditions and cut out. Further results of natural frequencies for several examples are compared with the results available in literatures for evaluating accuracy of displacement models. Computer programs are developed for automatic meshing of laminated composite plate, and for dynamic analysis to obtain natural frequencies and mode shapes.