Static and Dynamic Buckling of a Daedalos Composite Panel Including Material Damping

A three-stringer composite panel manufactured by IAI, measured by TECHNION and materially characterized by POLIMI is analyzed by aid of FEM using, the FOI in-house higher-order FE-code STRIPE and a brick element model with quartic displacement interpolation. Quasi-static and transient dynamic analyses are performed. Comparisons are made using a loading function yielding quiescent initial condition. A stacked composite description is used. The laminate theory elasticities are determined using the stacking information. The loading rate is low and the inertia and damping effects are small, but visible. Primary, loss of uniqueness as well as the ultimate limit load are influenced by inertia and presence of damping. The panel displays a clearly visible multimodal buckling behavior. The panel and stringer buckling are close and coupled. The panel shows multiple force redistributions associated with snap like buckling shape changes. The ultimate loss of load-carrying capacity is caused by the buckling of the middle stringer. Finally, the numerical predictions are compared with the experimental results.