A comparison of crashworthiness methods for the assessment of ship damage extents

The dynamic response of ships subjected to grounding and collision accidents may be influenced by structural topology as well as operational and environmental conditions. Traditionally, the consequences of such events may be assessed by crude empirical methods or laborious experiments. Computational methods offer a useful alternative in terms of accurately capturing crushing mechanisms also accounting for the influence of surrounding water. This paper presents two benchmark studies (ship-ship collision and ship grounding) that compare the structural dynamic response simulated by explicit nonlinear FEA and super-element approaches. Special attention is attributed to breach comparison as well as dissipated energy. Simulations for typical accident scenarios involving passenger ships confirm that accounting for the effect of hydrodynamic forces in way of contact is crucial for either collision or grounding analyses. Yet, for grounding scenarios, the breach size resulting from numerical simulations appears to be particularly sensitive to the failure strain values adopted to model the rupture of the ship bottom.