Estimation of Ultimate Strength of Ship Bottom Plating under Combined Transverse Thrust and Lateral Pressure

Abstract

A simplified method of estimating the ultimate strength of ship bottom plating under combined transverse thrust and lateral pressure is presented. A series of elastic/elastoplastic large deflection analyses is performed to clarify the influence of lateral pressure on both elastic buckling and ultimate strengths of a continuous plate. Based on the obtained results, a set of formulae has been derived for the estimation of the ultimate strength. Two fundamental collapse modes are recognised for a continuous plate under combined transverse thrust and lateral pressure i.e. simply-supported mode and clamped mode. For the former collapse mode, the increase of ultimate strength as a result of the increase of elastic buckling strength under lateral pressure is taken into account. The effect of lateral pressure on the yielding of plate is considered for both collapse modes. The ultimate strength is estimated taking the lower strength between those obtained for the two assumed collapse modes. It has been found from a comparison of the predicted strengths with the FEM results that the proposed formula gives very accurate prediction of the ultimate strength of a continuous plate under combined transverse thrust and lateral pressure.