Development of a multiobjective optimization procedure for reducing edge delamination stresses in composite plates

This paper addresses the development of an optimization procedure for the reduction of interlaminar stresses in composite plates. The goal is to reduce the interlaminar stress trends near the free edges of composite plates subjected to single and combined loadings. A simplified analytical approximation is used for predicting the free edge delamination stresses. Ply orientations are used as design variables and constraints are imposed on the in-plane material-axis ply stresses, the buckling load and the interlaminar normal stress interior to the free edge of the plate. The problem is formulated with multiple design objectives and the Kreisselmeier-Steinhauser multiobjective optimization technique is used to solve the nonlinear problem. The procedure yields significant reductions in the interlaminar stresses. Results are presented and compared with a reference or baseline design for four Gr/Ep composite plates with symmetric ply arrangements.