In the large heat input weld joint of heavy gauge steel plate used for large container carrier, a brittle crack possibly propagates straightly along a weld joint without diverging to base metal. This phenomenon is being discussed for its application to the large heat input weld of heavy gauge plate to ship structures. In this study, to arrest a brittle crack at Tee joint embedding un-welded face, the effect of un-welded face on behavior of brittle crack propagation/arrest in Tee joint structure was investigated and analyzed. The ESSO test of Tee joint structure was carried out, supposing that a brittle crack which propagates along a weld joint of hatch coaming rush into Tee joint of hatch coaming and strength deck. The test results exhibited that the brittle crack arrested at the Tee joint embedding un-welded face, and the brittle crack arrested easier, the longer un-welded face was. The results of static FEM analysis showed that stress intensity factor of brittle crack was increased by un-welded face, until brittle crack reached a flange. However, when brittle crack propagate into the flange, stress intensity factor of brittle crack was decreased by un-welded face for instance. The crack-arrest effect of un-welded face appears remarkably after brittle crack propagates into the flange.
