Progressive Failure Analysis Using Global-Local Coupling Including Intralaminar Failure and Debonding

Composite laminate stiffened panels are often used in aircraft fuselage design because of their favorable properties. To assess the failure load of these thin-walled structures and to exploit their reserves, a reliable simulation capability for their postbuckling behavior is often necessary. To perform a realistic failure analysis and to accurately detect final collapse, material degradation should be considered. Global-local approaches are computationally efficient techniques to perform a progressive failure analysis and to examine localized damaged areas in detail. In this paper, a two-way coupling global-local approach is presented, including a combination of different damage modes, such as matrix cracking, fiber damage, and skin-stringer debonding. An accurate exchange of information concerning the damage state between global and refined local models is performed. From the global to the local model, the displacements are transkrred through a submodeling procedure. Afterward, the degraded material properties obtained from the local model analysis are returned to the global model with a special mapping technique that accounts for the different mesh sizes at the two levels. The two-way coupling procedure is applied to the progressive failure analysis of a one-stringer composite panel loaded in compression. Finally, the numerical results of the procedure arc compared with experimental results.