Evaluating structural crashworthiness and progressive failure of double hull tanker under accidental grounding: bottom raking case

Abstract

Abstract Remarkable consequences of maritime accident can be various, including structural damage, loss of life and marine pollution. During an accidental phenomenon, such as ship grounding, the amount of oil spillage indicates casualties’ extent of surrounding sea water. Effort to provide protection for sea environment against such event has been conducted actively by developing navigational instruments, and passively using structural development and assessment. The accidental grounding is, however, a very complicated process with high sensitivity to given factors during its occurrence. Variety in ship type, location, obstruction etc. affected by advance improvement in naval technology, invites sustainable analysis for structural crashworthiness and failure to produce evaluation data. This work aims to perform an assessment on double hull tanker subjected accidental grounding with oceanic seabed as the obstruction. Fundamental concept of bottom raking is used to design grounding scenario using numerical experiment. Non-Linear Finite Element Method (NLFEM) is deployed to idealise tanker structure and obstruction geometry. The selected crashworthiness criteria in grounding are summarised to provide structural prediction in moment double hull members are experiencing crushing process. Influence of geometrical parameters’ variation to progressive failure is presented with contribution of double bottom members to structural behaviour in final part. Result data of the current work can be a reasonable reference to understanding double bottom performance in grounding, especially in raking case. Insight of such accidental phenomenon is very useful in further effort to minimise grounding consequences.