The Mechanical Performance of Cross-Plied Fiber Glass-Epoxy Composites

Abstract : Tensile tests were conducted on glass epoxy cross-ply laminates having either predominantly brittle or ductile epoxy matrices. The ductile system exhibits far better mechanical performance that the brittle counterpart, especially when the transverse plies are on the outside. This was reflected by significantly higher initial and ultimate strength values, slower crack propagation in the transverse layer, higher strains at failure and better toughness at off-axis orientations. In both ductile and brittle systems the laminae have higher strength, stiffness and toughness than their unidirectional references. This improved performance is a result of the interaction between the two perpendicular layers which gives them additional stiffness due to shear and transverse coupling effects and also increases the resistance of each individual layer to crack propagation and plastic flow.