An innovative modeling strategy for flexural response of fiber-reinforced stiffened composite structures

The use of composite stiffened panels is common in a large variety of engineering structures. An advanced computational model is developed to accurately predict the complex behavior of laminated composite stiffened panels having thin-walled open or closed section stiffeners with in-filled materials. In the approach proposed, the plate and stiffeners are discretely modeled using 2D plate elements for the skin or plate, and 1D beam elements for the stiffeners, where the deformations of the stiffeners are completely expressed in terms of deformations of the plate to minimize the number of unknowns. The key novelty in this study is the model formulation of the stiffeners, which is based on a rigorous cross-sectional analysis to include all effects including out-of-plane and in-plane warping along with their couplings. To validate the proposed model, numerical examples of stiffened panels with different stiffener cross-sectional geometries and composite layups have been analyzed and benchmarked against results from the literature. Moreover, the predictions of the new model have also been successfully compared against detailed finite element model results to study the behavior of stiffened panel configurations, which are not available in the open literature. The results predicted by the proposed model confirmed a very good performance in terms of accuracy and range of applicability.