Thickness Effect on the Brittle Crack Arrest Toughness Value (Kca): Brittle Crack Arrest Design for Large Container Ships -6

摘要

Brittle fracture of the hull structure has the possibility to cause seriousstructural damage and so it should be avoided. Therefore, it isimportant to ensure the hull structural integrity by preventing brittlecracks from being initiated and also by providing a proper means forarresting the brittle crack when the crack propagation occurs.In the last 4 papers of ISOPE 2010, the authors investigated a properbrittle crack arrest design for large container carriers by carrying out anumber of large scale and middle scale fracture tests. As a result, it wasconcluded that the required brittle crack arrest toughness value Kcashould be more than 6000N/mm~(3/2) to arrest brittle cracks in thick steelplates exceeding 50mm.The issue of the plate thickness effect on the required Kca has become akey concern with regards to the applicability of the proposed Kca.Since 2009, the authors conducted ultra-wide duplex ESSO tests withplate thickness from 25mm to 75mm, which had no structuralinfluences on the test results, in order to investigate the thickness effecton the required K_(ca) value. As a result, it was confirmed that platethickness affects the required K_(ca) value.