Fatigue Collapse of Ship Structural Components: a Case Study

Most damages to structural components of ships are due to fatigue phenomena. Particular care should then be devoted to fatigue evaluation since the first phases of any ship project. All main Classification Societies have in their Rules simplified procedures for fatigue evaluation, in order to make all designers able to perform structure scantling complying with fatigue principles. Apart from design necessities, there is another aspect for which it becomes important to assess and evaluate fatigue phenomena; this happens when it is necessary to ascertain the causes of occurred an accident. While for design purposes the aim is to calculate the fatigue life of a structural detail based on a probabilistic approach, in the case of an occurred accident the driving philosophy is to accurately analyse the life history of the structure and to calculate, by a deterministic approach, the cumulative damage of the component up to the event time. The aim of this paper is to set up a procedure to analyse and verify the causes of the failure of a ship structure component due to fatigue phenomena.