Ultimate Longitudinal Strength of Ships' Hull Girder under Combined Loading

It is necessary to make clear the effect of torsional moment on the ultimate strength of the ships' hull girder for the accurate assessment of that of ultra large container ships with large deck openings. In the present study, the extension of the simplified method of progressive collapse analysis based on Smith’s method is attempted to the case of combined loading condition. Firstly, progressive collapse tests are carried out on 1/13-scale three-hold hull girder models referring to a Post-Panamax container ship. The models are fixed to the rigid wall at the aft end and a couple of forces are applied to the fore end so as to generate torsional and vertical bending moment simultaneously. The progressive collapse tests are conducted for the case of the various combinations of torsional and bending moment. The nonlinear finite element analyses by LS-DYNA are executed in accordance with the test conditions. From the test and calculation results, the progressive collapse behavior and the ultimate strength of hull girder models under combined loading are examined. The results will be a basis for the verification of a new simplified analysis method which will be presented in the forthcoming reports.