Abstract
Delamination of reinforced polymer materials is one of the catastrophic and an unsolved mystery for composite structures. Very often, a composite structure under shear loading experiences an interlayer fracture. Among many of the fracture modes, crack initiation due to the failure of the matrix is very common. The polymer matrix is weaker in mechanical properties than the fibers and shows inferior shear performance under different loading conditions. In this study, epoxy layers under shear loading have been analyzed by cohesive contact generated by the finite element method by ABAQUS. The development of stress and failure features have been identified by existing cohesive zone theories. A comparative analysis has been performed for composite structures fabricated with neat epoxy and epoxy modified with electrospun carbon nanofiber. The qualitative study indicates composites structure fabricated from nanomaterial modified matrix may show different cohesive zone. Therefore, composite materials reinforced with an additional phase in the matrix may exhibit different delamination mechanics under short beam shear loading. A detailed analysis of the cohesive contact parameters has been introduced and to characterize the delamination behavior in the matrix layer in between the interlaminar region has been discussed. The current study indicates a change in the cohesive zone is necessary for better representation of nanofiber modified epoxy contact than the conventional epoxy layer analysis.