FLEXURAL BEHAVIOR OF STEPPED GRAPHITE-EPOXY LAMINATES

Cross-ply tapered/stepped laminates with taper angles of 1 and 2-degre es between the top and bottom surfaces were fabricated using T300/934 graphite/epoxy by compression molding. Ply terminations were done inte rnally within the laminate and externally on the surface of the lamina te at various cross-sections in order to obtain the taper. Equivalent cross-ply specimens with internal and external ply terminations, respe ctively, were tested in three point bending. The bending stiffness of the equivalent cross-ply beams are nearly equal, while the failure mod es are significantly different. The tapered laminates with internal pl y terminations failed due to a series of delaminations originating at the step comers of the 0-degrees plies. Macroscopically, the specimens with internal ply terminations failed by tensile fracture of the oute r plies at relatively higher loads.