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Characterization, analysis and prediction of delamination in composites using fracture mechanics

The state-of-the-art for characterizing, analyzing, and predicting delamination growth in composite materials and structures using a fracture mechanics approach will be reviewed. Techniques for measuring delamination fracture toughness and fatigue delamination onset data will be highlighted. The use of these data in finite element analyses utilizing fracture mechanics will be examined. The virtual crack closure technique for calculating strain energy release rates will be highlighted. The importance of capturing the physics of damage formation, accumulation, and growth will be emphasized. Application of this approach to delamination onset and life predictions for stiffener pull-off behavior in skinstiffened regions and fatigue failure of composite rotor hub flexbeams will be highlighted.