Experiment study of hydroelasto-buckling ship model in a single wave

Abstract

A single wave of extreme height can damage ship structures in the ocean by generating buckling midship, thus destabilizing the ship girder and causing rupture. The probability of such an extreme wave is low in reality. On the one hand, it is very costly to recreate a real ship test for the study of extreme wave conditions. On the other hand, it is difficult to carry out tests on a scale model in tank waves, because such waves are too small to damage the ship model. In this paper, a hydroelasto-buckling experiment is performed on a ship model to study the dynamic ultimate strength of the ship and dynamic course of collapse of the structure. Thus far, no method of simulation has been proposed to study this problem because the dynamic ultimate strength of the ship involves strong coupling between the nonlinearity in the ship structure and waves. Here, a hydroelasto-buckling ship model is first designed, and a test programme is determined. A buckling hinge that can collapse under the load of the tank wave is used to connect two ship girders with a hinge joint. Then, a number of single tank waves are generated by changing their wave patterns to simulate an extreme ocean wave. The dynamic rotation angle, bottom water press and acceleration at midship are measured in the experiment. Importantly, the relationship between structural response and wave patterns is analyzed. The structural response involves encountering the VBM/rotation deformation induced by the wave load and whipping the VBM/rotation deformation induced by natural structural oscillations. It is found that the ultimate strength of the ship girder can be generated by both encountering waves and the structural flutter response caused by changing wave height. Lastly, the midship water pressure and acceleration are also analyzed to discuss the influence of a large deformation of the ship structure on the fluid load. Some conclusions are presented in the paper.