抄録
Crack initiation and propagation process in delayed fracture of high tensile strength steel bolt have been studied by Fracture-surface topography analysis (FRASTA) method. The delayed fracture process thus involves a series of crack initiations rather than the continuous growth of a single crack. Crack initiates at the region of maximum triaxial-stress state. After first crack initiation, new cracks initiate at new regions of sever triaxial-stress state, and these cracks join in propagation process.
