Experimental and numerical investigations on the collapse behaviour of box type hull girder subjected to cyclic ultimate bending moment

Abstract

This paper presents experimental and finite element analyses of the ultimate strength and buckling collapse behaviours of a single- and a double-hull girder with a large deck opening subjected to cyclic ultimate bending moments. The cyclic ultimate bending moments here means that the external load in every cycle exceed the ultimate load bearing capacity of the specimens; the aim is to understand how the structures behave under this kind of extreme but not unusual load condition. The results showed that, in general, the plastic deformation would be accumulated under the cyclic loads, and the buckling collapse would expand from the deck plates to the broadside plates in both specimens. However, even if overall buckling occurred on both specimens, the specimens still preserved most of the load bearing capacity for the next ultimate loading cycles, but the double-hull specimen had a higher safety stock. In addition, the different behaviours of these two types of specimens were recorded, and the reasons behind were deeply analysed, which has helped us gain a deeper understanding of how these complex engineering structures perform under this kind of extreme but not well-studied load condition. The conclusions drawn in this works would be beneficial to improve the structural safety of ship hull girders and other similar thin-walled structures.