Development of Crashworthy Bottom and Side Structures

The purpose of this work is to compare the resistance to damage of various types of double bottom structures in a stranding event. The results can also be interpreted as the crashworthiness of side structures penetrated by a striking vessel in a collision event. The comparative analyses are made by use of a commercial, explicit finite element program. The ship bottom is loaded with a conical indenter with a rounded tip, which is forced laterally into the structures in different positions. The aim is to compare resistance forces, energy absorption and penetration to fracture for four different structures. The first structure is a conventional double bottom. In the second structure (presently protected through a patent) the bottom plating is stiffened with hat-profiles instead of bulb profiles. In the third structure the outer shell is an all-steel sandwich panel. In the fourth structure the bottom and the inner bottom plating are stiffened with hat-profiles. The paper shows that it is indeed possible to elevate the crashworthiness of side and bottom structures with regards to the loading considered here without increasing the structural weight.