Formulating Test Specimen Thickness Effect on Fracture Toughness With T33-Stress: Case of 3PB Test Specimen

This paper considered the test specimen thickness effect on the fracture toughness of a material, in the transition temperature region, for 3PB specimen. Then, the thickness effect on the T33-stress, which is the out-of-plane elastic crack tip constraint parameter, was studied. Finally, an experimental expression on the thickness effect on the fracture toughness by using T33-stress was proposed for 0.55% carbon steel S55C. The results seemed to indicate a possibility of improving the existing methods to correlate the fracture toughness obtained by test specimen with the toughness of actual cracks found in the structure, in use of T33-stress.