Estimation of Ultimate Strength of Continuous Stiffened Plate under Combined Biaxial Thrust and Lateral Pressure

Abstract

The authors proposed a set of closed-form simple formulae to estimate ultimate strength of a continuous stiffened plate under combined longitudinal thrust, parallel to stiffener direction, and lateral pressure. This paper extends the application of the formulae to biaxial thrust condition based on a series of elastoplastic large deflection FE analyses. It was found from FEA that the ultimate strength of a continuous stiffened plate under transverse thrust is significantly higher than that of a continuous unstiffened plate simply-supported along stiffener lines because of a stiffener's torsional stiffness. It was also found that there exist two fundamental failure modes; one is local failure mode of plate between stiffener under predominantly transverse thrust and the other is over-all failure mode of stiffened plate under predominantly longitudinal thrust, and that the ultimate strengths corresponding to the respective failure modes can be estimated rather independently, with little interactions. Based on these observations, a set of simple ultimate strength formulae has been derived, and their validity has been confirmed through a comparison with FEA results.