A method for progressive structural crashworthiness analysis under collisions and grounding

Collisions and grounding always give rise to structural crashworthiness issues involving crushing, yielding, and fracture. For accidental limit state design and safety assessment associated with collisions and grounding, the resulting progressive structural crashworthiness characteristics should be analyzed to evaluate the energy absorption capability of the structure in the corresponding accidental event in conjunction with the associated criteria. The accidental energy absorption capability of a structure under collisions or grounding can be predicted by integrating the area below the reaction forces versus penetration curve until or after the accidental limit state is reached. For risk assessment associated with such accidents, the results of structural crashworthiness analysis are also used as a basis of the consequence analysis. The aim of the present paper is to present an efficient and accurate method which is useful for the progressive structural crashworthiness analysis of ships and ship-shaped offshore structures under collisions or grounding. Theoretical outline of the method is addressed. Application examples of the method to ship-shaped test structures are presented by a comparison with experimental results.