A post-buckling compressive failure analysis framework for composite stiffened panels considering intra-, inter-laminar damage and stiffener debonding

A post-buckling failure analysis framework was established to accurately and thoroughly capture the post-buckling deformation paths and failure processes as well as bearing capacities of composite stiffened panels under uniaxial compression. In this framework, the progressive damage method to thoroughly track the intra- and inter-laminar damage in laminates, the cohesive zone method to accurately examine the stiffener debonding damage, and the arc-length iteration algorithm to tracking the geometrical nonlinear post-buckling path, were all introduced. Post-buckling failure processes of a blade-stiffened panel and a large-scale hat-stiffened panel under uniaxial compression were systematically investigated. Computation cases with various damage models were designed and implemented, and the effects of intra- and inter-laminar damage, stiffener debonding, and their potential interactions on the post-buckling failure process of the stiffened panel were clarified. The predicted post-buckling failure processes of both panels were highly consistent with their experimental outcomes, thus giving evidence of the effectiveness of the failure analysis framework. It follows that a comprehensive failure mode characterization including intra- and inter-laminar damage, stiffener debonding should be all considered in a failure analysis framework for accurately predicting the failure of composite stiffened panels in engineering applications.