DAMAGE PREDICTION AND ITS EFFECT ON POST-BUCKLED WING DESIGN

Over the last few years there has been an increase in the use of laminated carbon fibre reinforced plastics (CFRPs) in military and civil aerostructures, mainly due to their superior specific strength and stiffness. Reducing the extent of mechanical fasteners by co-curing, co-bonding or secondary bonding the stiffeners to the skin offers the possibility of significantly lighter structures and lower production costs. Additionally, stiffened composite structures have been shown to be able to support load beyond initial local skin buckling. However, the confidence in composite structure designs which allow buckling has yet to be widely adopted, predominately due to the unpredictability of their degradation during post-buckle loading. This unpredictability stems from a number of complicated failure mechanisms and how they are affected by buckling mode-switching behaviour. This paper discusses prediction methods of structural buckling and damage modelling in postbuckling stiffened composite structures under uniaxial compression. Good agreement has been obtained with experimental results. Implications of the effect of in-service damage on post-buckled panels are then discussed. The work has provided confidence in the use of a promising tool for future design as well as suggesting how post-buckled design can by used in the optimisation of future aerostructures