Fatigue Assessment of Block Joints on Passenger Ships and a Proposal for Innovative Technical Solutions

This work examines innovative solutions for the welded connections that join the large preassembled substructures that compose ships. In the most common shipyard practice, the block joints are made by means of full penetration butt welds on both plates and stiffeners, and the misalignments between the elements can cause high stresses in a location where a stress concentration already exists. The outlined critical situation induces to consider new solutions in order to minimize the detrimental effects on the fatigue life of the structures. A study has been carried out on block joints typical of passenger ships (where the low thicknesses imply more critical misalignment effects). Qualities and deficiencies of different possible solutions have been examined in order to enable the designer to advisedly choose the configuration that can best withstand cyclic loads in presence of the misalignments that usually can be found.