OPTIMUM DESIGN OF COMPOSITE LAMINATES FOR STRENGTH BY RANKING

In this paper we describe a method for the optimum design of fiber reinforced composite laminates for strength by ranking. The software developed based on this method is capable of designing laminates for strength; which are subjected to inplane and/or bending loads and optionally hygrothermal loads. Symmetric laminates only are considered which are assumed to be made of repeated sublaminate construction. Various layup schemes are evaluated based on the laminated plate theory and quadratic failure criterion for the given mechanical and hygrothermal loads. The optimum layup sequence in the sublaminate and the number of such sublaminates required are obtained. Further, a ply-drop round-off scheme is adopted to arrive at an optimum laminate thickness. As an example, a family of 0/90/45/-45 bi-directional lamination schemes are examined for different types of loads and the gains in optimising the ply orientations in a sublaminate are demonstrated.