ABSTRACT
Side shells of passenger ship’s superstructure have important part in shear force carrying capacity of hull girder. The importance of side shells is increasing in modern designs because the amount of longitudinal bulkheads is decreasing in superstructure. At passenger deck levels side shells are full of openings including windows and doors. Side shell of big cruise liner can include thousands openings. The trend is that the size of openings is increasing. Clearly the critical design detail exists at the window and door corner area due to stress concentration (Fig. 1). Detail design of the corner area has become increasingly important. It is necessary to check both the maximum stresses as well as the fatigue strength of this detail. (Bäckström & Kivimaa 2008)
The fatigue process can generally be broken into two distinct phases: initiation and propagation phase of the crack. The initiation phase is usually short in the welded structures because it can always be assumed that sharp-edged discontinuities exist in a welded structure. The fatigue life estimations for welded structures with discontinuities can be based on the crack propagation calculation by using fracture mechanics.
