Progressive Failure Analysis of Cross-ply Laminated Composite Plates by Finite Element Method

Abstract

The progressive failure analysis of laminated composite plates under transverse static loading has been carried out in the linear and elastic range. The laminated composite plate has been modeled using eight-noded isoparametric plate bending elements. The first-order shear deformation theory has been employed to account for the shear flexibility characteristics through the thickness direction of a composite laminate. A shear correction factor has been considered to reduce discrepancy between the assumed constant shear strain and the actual parabolic variation of the shear strain in the transverse direction. The mid surface of the laminate has been considered as the reference plane in the present formulation. After the failure of the weakest ply, the stiffness is reduced by either fiber failure or matrix failure. The stiffness of failed lamina has been totally discarded and other existing laminae are considered to remain unchanged after the weakest ply failure. The strength of the laminate at the same point is evaluated again to see if the laminate can carry additional load. This ply-by-ply analysis progresses until the ultimate strength of the laminate is reached. The results in terms of first-ply failure load obtained in the present investigation have been compared with those available in published literature. A parametric study has been carried out to estimate the influence of stacking sequence, fiber orientation, layer thickness, aspect ratio and the number of layers in the laminated composite plates on the prediction of ultimate failure load.