What Can We Learn From Uncertainty Analysis With Respect to Survivability or Time to Capsize of a Ship Struck in Collision?

Collisions between ships contribute to ship losses even in modern time, and the International Maritime Organization (IMO) strives towards a more risk-based view on addressing the damage stability of ships. The current paper makes use of a methodology for computing the consequences of ship collisions. This methodology is comprised of structural analysis of a collision scenario followed by dynamic damage stability simulations of the struck ship. The emphasis of this investigation is on uncertainties related to structural computations of the collision event. Explicit finite element analyses are presented for a case study of a collision scenario. For comparison, the model of the bow of the striking ship is considered as either rigid or deformable in separate analyses. The consequences from the model representation of the bow, uncertainties in material properties and failure model (three different ones are presented) in terms of shape and size of the damage opening are studied. This variation also has an impact on the time to capsize of the struck vessel, which is studied in the subsequent damage stability computations for different sea states. One conclusion is that the methodology that has been used is important for future efforts in the research on safety at sea. The study presented demonstrates the importance of incorporating uncertainties in the analysis chain and studying the effect of these on the final results: the time to capsize.