Considering usual computation efforts, single-frame models are used in the ultimate strength analyses of container ships. However, the case of large container ships is more complicated, and further investigations should be made. Generally speaking, the modeling extent, boundary conditions, lateral pressure, and initial deflection are key factors in the ultimate strength analysis. As a case study, we investigated their influences on ultimate strength under both vertical bending and torsion cases for a typical 10,000 twenty-foot equivalent unit (TEU) container ship, and also bending–torsion interactions. The results are representative and can be reference values for container ships of similar sizes.
Container ships are getting larger, and their structural strengths are major concerns for their owners and designers, especially after the 2013 crash of the MOL Comfort, an 8,110 twenty-foot equivalent unit (TEU) container ship. According to technical investigations (ClassNK, 2014), the local deformations of local structures such as double bottom are not negligible, which, however, has not been systematically considered previously. Thus, further investigations of large container ships to better understand their specific structural behaviors are meaningful.