EQUIVALENT PLATE MODEL OF CURVILINEAR STIFFENED PANELS

This manuscript presents the derivation of a systematic set of equations for the evaluation of equivalent plate model of curvilinear stiffened panels. The homogenized properties of the stiffened panel are derived by first imposing kinematic equivalence between the stiffener’s strains and the strains of the equivalent layer, and then equating the strain energy density among the stiffeners and the equivalent layer among the real and the equivalent structure. The derivation is based on the first-order transverse-shear deformation theory for anisotropic plates (Reissner-Mindlin type). The stiffeners are modelled consistently using the FSDT beam theory (Timoshenko). It has been demonstrated that, if the stiffener are curvilinear, the derivation can be extended in order to derive the apparent engineering constants of the stiffened layer. A comparative study has been performed to evaluate the number of sub-cells necessary to approach the asymptotic value of the stiffnesses. The effect of the stiffeners’ geometry onto the engineering constant has been investigated. To assess the validity of the proposed method, a comparative study of the buckling loads obtained with a 2D shell model and those obtained with the equivalent plate/material model is carried out.