ABSTRACT
Hysteresis, the term can be applied strictly when the deformed material returns to the original shape (1). Most previous work on hysteresis has been carried out mainly on specimen with uniform geometries such as tensile specimens. When a precrack specimen is under tensile or bend loading prior to the onset of crack initiation (during crack-tip blunting), significantly higher strain is expected in the immediate vicinity of the crack tip. This will lead to local energy dissipation from both viscoelastic and inelastic mechanisms. The stored energy available for crack initiation or extension now should be the input energy minus the hysteresis (loss) energy (1). Material is considered tougher if it can better withstand or resist crack initiation and sometimes it will shift the failure from brittle mode to ductile mode.
