Arrestability of brittle cracks is extremely important in the structural integrity of welded joints of heavy gauge steel plates used in large container ships. Recently, a great attention has been focused on potential crack propagation along welds made with large heat input.In this study, a T-joint is applied to the strength deck structure of container ships to enhance crack arrestability. Material crack arrest toughnesses, Kca, of some steel plates are varied. The ESSO tests of T-joint components showed that a brittle crack is arrested at the T-joint if the steel plate used in the flange has a high Kca value in the range from 4900 to 7300 N/mm3/2.FE-analyses of the stress intensity factor K indicated that brittle crack propagation is arrested under the condition that the K-value at the running crack tip is less than the Kca of the material. It is noted in the T-joint that the K-value at the deepest point of the crack decreases and is finally below the Kca of the flange plate when a brittle crack rapidly penetrates the flange plate to a depth of 30-40mm. These phenomena show the advantage of the T-joint in brittle crack arrestability in the flange plate of the strength deck structure.
