Ply-by-ply failure analysis of laminates using finite element method

Abstract

Ply-by-ply failure analysis of anti-symmetric and symmetric laminated composite plates under uniformly distributed transverse load is carried out in this study. The successive failure analysis includes the determination of ply-by-ply failure load along with the failure mode using different stress-based failure theories. Ply-discount material degradation model is adopted to modify the properties of the failed lamina. The laminate has been modeled using eight noded isoparametric plate bending element having seven degrees of freedom at each node. A computer code is written using FORTRAN based on finite element formulation. The first-ply failure load has been compared with the reported results and a good conformity is found. Further comparison of different failure theories is made based on their ability to predict the failed ply, failure load along with the failure mode. The results are computed for both angle-ply and cross-ply laminates with simply supported and clamped edges. The importance of stacking sequence in terms of strength of the laminate is highlighted in the study.