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 i s to reduce the interlaminar stress trends near the free edges of comp osite plates subjected to single and combined loadings. A simplified a nalytical approximation is used for predicting the free edge delaminat ion stresses. Ply orientations are used as design variables and constr aints are imposed on the in-plane material-axis ply stresses, the buck ling load and the interlaminar normal stress interior to the free edge of the plate. The problem is formulated with multiple design objectiv es and the Kreisselmeier-Steinhauser multiobjective optimization techn ique is used to solve the nonlinear problem. The procedure yields sign ificant reductions in the interlaminar stresses. Results are presented and compared with a reference or baseline design for four Gr/Ep compo site plates with symmetric ply arrangements.