Dynamic characteristics of stiffened composite panels using an efficient stiffener element formulation

This study investigated the dynamic responses of composite stiffened panels having multiple eccentric stiffeners with thin-walled open or closed in-filled sections. For this purpose, an advanced modeling technique having good accuracy was developed, where 1D beam elements and 2D plate elements are used to model the stiffeners and the plate/skin, respectively. The main innovation of this study lies in the formulation of stiffeners, which incorporates both in-plane and out-of-plane warping, coupled through a rigorous cross-sectional analysis. Moreover, stiffener displacement was fully expressed in terms of plate displacement to achieve better computational efficiency. To demonstrate the efficiency of the proposed approach, the study undertakes several dynamic analyses including free and forced vibration of composite stiffened panels having various composite arrangements and stiffener cross-sectional geometries. The numerical results were compared against credible published results to validate the present model, which confirmed the model’s accuracy and its applicability across a wide range of scenarios.