An Empirical Formula for Predicting Elastic Ultimate Buckling Strength of Flat-Bar Stiffened Panels With Initial Imperfections

Elastic ultimate buckling strength is an important strength design criteria to estimate the safety margin of stiffened panels subjected to axial compressive load. Based on a series of Nonlinear finite elements analysis, an empirical formula is proposed to elastic ultimate buckling strength of stiffened panels with flat-bar stiffener in this study. The elastic ultimate buckling strength is defined as that in the loading process, a certain average compressive stress of stiffened panels when the Vonmises stress of structures firstly reach the yield stress. The range of geometrical sizes for numerical samples is discussed in order to ensure the applicability of presented empirical formula. The extent of models and initial imperfection, namely initial geometrical deformation are also taken into account. Ultimately, it is shown that there are a good agreement between the results of Non-linear finite element method and the proposed empirical formula.