First ply failure analysis of stiffened panels – a finite element approach

A first-ply failure analysis method has been developed for predicting the failure load on the laminated composite stiffened panels under various loading conditions. The present finite element formulation is generalised to analyse both laminated bare/stiffened plate and shell panels elegantly. Eight noded isoparametric quadratic elements for shell and three noded curved beam elements for the stiffener are used for the analysis of stiffened panel. The stiffness matrix of the stiffener is computed independently and then transferred to that of the shell. The formulation eliminates the restriction on the location and orientation of the stiffener within the shell element. Several prominent failure theories have been considered in the present work for the prediction of failure load. The results obtained by the present formulation have been compared with those available in literature and some parametric study has also been performed on the basis of variety in shell geometry.