Abstract: Fracture test and finite element analysis of two different sized notched tensile bars at low temperature are carried out. It shows that cleavage fracture initiates from the location ahead of the notch, not from the root of notch where the elastic stress is maximal. The stress distribution isn’t elastic at fracture but elastic-plastic, so the result of elastic finite element analysis is contrary to the experimental results, otherwise, the result of elastic-plastic finite element analysis accords with the experimental results. Based on cleavage fracture local approach theory, numerical simulation method is used to predict cleavage fracture probability-load curves of notch bars with different radius. The study shows that the predicted load value corresponding to 44% cleavage fracture probability of a structure is almost equal to the average value of actual cleavage fracture load. Based on this, the variation trend of cleavage fracture load vs. different notch radius is predicted and verified by test.

Key words: Cleavage fracture, Local approach, Low temperature, Notch bar, Numerical simulation