抄録
abstract- This paper considered the test specimen thickness (TST) effect on the fracture toughness of a material J_c in the transition temperature region for 3 point bending (3PB) specimens. Based on the results, it was demonstrated that the "planar" (4δ_t,σ_<22c>) failure criterion-which states that cleavage fracture after significant plastic deformation occurs when the crack opening stress δ_22 at a distance from the crack-tip that is equal to 4 times the crack-tip opening displacement exceeds a critical value δ_<22c>-was verified to effectively explain the TST effect.
