Advanced ultimate strength formulations for ship plating under combined biaxial compression/tension, edge shear, and lateral pressure loads

The aim of the present study is to develop more advanced design formulation s for the ultimate strength of ship plating than available at present. Plat e ultimate strength subject to any combination of the following four load c omponents-longitudinal compression/tension, transverse compression/tension, edge shear, and lateral pressure loads-is addressed. The developed formula tions are designed to be more sophisticated than existing theoretically bas ed simplified methods. The influence of post-weld initial imperfections in the form of initial deflections and residual stresses is taken into account . It has been previously recognized that a single ultimate strength interac tion equation cannot successfully represent the ultimate limit state of lon g and/or wide plating under all possible combinations of load components in volved. This is due to the fact that the collapse behavior of the long and/ or wide plating depends primarily on the predominant load components, imply ing that more than one strength interaction formulations may be needed to m ore properly predict the plate ultimate limit state. In this regard, the pr esent study derives three sets of ultimate strength formulations for the lo ng and/or wide plating under the corresponding primary load by treating lat eral pressure as a secondary dead load. The ultimate strength interaction f ormula under all of the load components involved is then derived by a relev ant combination of the individual strength formulas. The validity of the pr oposed ultimate strength equations is studied by comparison with nonlinear finite-element analyses and other numerically based solutions.