Evaluation Method of the Brittle Fracture Strength in Structurally Stress-Concentrated Regions

A series of researches has been conducted, based on CTOD concept in order to evaluate quantitatively the brittle fracture strength in structurally stress concentrated regions. As a result, it was made clear that the calculation of CTOD by BCS model, estimation of low temperature CTOD by non-dimensional indication, and the method using CTOD design-curve could be an effective means for evaluating the brittle fracture strength in stress-concentrated regions with defects. Particularly, in relation to the method using CTOD design-curve which could be the most general evaluation technique, new ideas for CTOD design-curve and welding residual stress have been proposed for more precise strength evaluation. These are actually being applied to the evaluation of brittle fracture strength of welded structures and have presented notable achievements.