Scale model tests for the post-ultimate strength collapse behavior of a ship's hull girder under whipping loads

In this paper, experimental investigations into the post-ultimate strength collapse behavior of a ship's hull girder under whipping loads are presented following the author's previous works based on numerical simulations. One of the important conclusions of the previous works is that given the same magnitude of the loads, the collapse extent is much smaller for the loads with the shorter duration. For the validation, a scale model with a scale ratio of 1/100 which follows a law of similitude in the ultimate bending strength as well as geometry is employed in tank tests. The whipping loads are produced by dropping a mass object and the time history of the whipping loads are pre-adjusted by tuning the object mass, cushion material and dropping height. The hull girder bending moment with the same magnitude and with a time duration ranging 0.5 s-1.5 s in real scale is applied to the hull girder. It was observed that the collapse extent was smaller for the loads with the shorter duration.