A refined stiffened plate element for stability analysis of the stiffened sandwich structures

The stiffened plate is one type of representative thin-walled structure consisting of plates reinforced by varying stiffeners to strengthen its resistance to buckling deformation. However, the mechanism by which stiffeners could efficiently improve the buckling resistance of such structures has not been well reported. Therefore, to investigate the mechanism and predict buckling behavior of the structures accurately, a refined Reddy-type global-local stiffened plate model (RGLS) is established firstly, which can fulfill continuous condition of in-plane displacement and transverse shear stress among the adjacent layers between the plate and stiffeners. In conjunction with the established model, a refined triangular element which can accommodate the continuous condition of transverse shear stresses at the interface between the plate and the stiffeners is constructed. Subsequently, on the basis of the unidirectional stiffened sandwich structures, the symmetric grid-stiffened sandwich structures are proposed. The buckling behavior of grid-stiffened structures is further explored by the present element. A full experimental study and a system of numerical examples have been performed to assess the reliability of the established elements. These examples demonstrate that the buckling loads could be captured by the developed element with high computational efficiency and accuracy. However, the models will significantly overrate buckling loads of the stiffened sandwich structures without considering the continuum condition of the transverse stresses at the plate-stiffener interface.