Damage Tolerance of Buckling Optimized Variable Angle Tow Panels

Elastic stiffness tailoring of composite panels with curved fibers, or Variable Angle Tows (VATs), for maximum buckling performance is presented. The panels are modelled efficiently using the exact finite strip program, VICONOPT, and are optimized using a Genetic Algorithm. VAT panel designs are compared with straight fiber panels and are shown to offer weight saving potential by increasing panel buckling loads. Finite strip analysis is also combined with a fracture mechanics model to predict the compressive strength (damage tolerance) of panels delaminated by impact damage. The analysis, which shows good agreement with experimental failure strains for straight fiber panels, is applied to the VAT designs. Results show that damage tolerance is critical for heavily loaded panels and for panels with closely spaced longitudinal supports.