Assessing buckling strength of stiffened plates as affected by localized initial geometric imperfections

Abstract

Abstract Considering a stiffened panel made from an elastic homogeneous and isotropic material which suffers a single localized initial geometric imperfection, assessment of the buckling limit state under in-plane uniform axial compression in the direction of stiffeners was performed. Giving a topological configuration of the stiffened plate, focus was aimed at the combined effect resulting from geometrical dimensions and localized defect characteristics. The perfect stiffened plate taken as reference and diverse imperfect stiffened plates suffering a single localized initial geometric defect of the form of a square depression were analyzed in this work. Extensive parametric finite element simulations were performed according to full factorial design of experiment tables that were built on key intervening factors. It was found that the main parameters controlling the buckling stress for the perfect plate are the plate width, then the web height and width, then finally the interaction between plate width and web height. In case of imperfect plates, the most adverse situation was obtained with the defect placed on the intermediate segments of the stiffened plate. A reduction of the buckling stress as low as 56% was reached in this situation. The main factors influencing the buckling load for the imperfect plate differ according to the defect configuration.