Structural Response of a Container Ship Against Beam Sea Wave

This study carried out nonlinear finite element analyses of an imaginary container vessel under beam sea wave conditions. Deformation and collapse behaviors of hull structures have been studied using finite element analysis, but many of them focused on the behavior under following and heading wave conditions, evaluating hull girder ultimate strength. Although recent requirements to assess hull structure strength employ beams sea wave, in addition to longitudinal wave, the structural response against beam sea wave has not been paid attention to. In particular, the transverse structures such as side transverse and side shell are supposed to be influenced by the beam wave conditions, but detail analyses of their deformation affected by yielding and buckling have been rarely conducted. A series of nonlinear finite element analyses using a so-called three-hold model of mid region of the container ship were carried out by applying the wave pressure, cargo load and inertia due to ship acceleration, and hull girder moment supposing the time of the maximum roll angle. The results reveal that the side shell undergoes elastic buckling, but the further deflection is suppressed by the neighboring intact side transverse because the compressive displacement of short sides of the side shell panels are constrained by the side transverse. Such behaviors were observed in analyses with different thickness of the side shell and side transverse. Such ‘surrounding’ structure effect might contribute to the hull structural integrity under beam sea waves.