Abstract
Fracture behavior showing ductile-to-brittle transition in steel is quite important for the assessment of structures against catastrophic failure. Recently various fracture assessment methods have been established. In such methods, all toughness data of target steel including ductile-to-brittle behavior must be collected before evaluation. Also consideration about ductile crack is not sufficient. This report picks up high strength steel and designs to clarify ductile-to-brittle behavior from standpoint of mechanics in two stages: i,e, 1)ductile crack initiation and extension 2)subsequent brittle fracture . Consequently it became clear that both of two stages could be evaluated by criteria obtained from simple small testing. This can indicate suggestions for more detailed fracture assessment in various structures and more rational material designing.
