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

Abstract

A series of experimental investigations on the post-ultimate strength collapse behaviour of a ship's hull girder under whipping loads are presented. It is a follow-up study of the authors based on numerical simulations. One of the important conclusions of the previous work is that given the same magnitude of the loads, the collapse extent is smaller for the loads with the shorter duration. For the validation, a scale model with a scale ratio 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. The time history of the whipping loads is pre-adjusted by tuning the object mass, cushion material and dropping height. The hull girder bending moment with a time duration ranging 0.5–1.5 s in real scale, however, with the same magnitude, is applied to the hull girder. It was observed that the collapse extent was smaller for the loads with the shorter duration.