New stress distribution scaling method to predict fracture toughness temperature dependency

In this paper, a new method for scaling the crack tip stress distribution under small scale yielding condition was proposed and named as T-scaling method. This method enables to identify the different stress distributions for materials with different tensile properties but identical load in terms of K or J. Then by assuming that the temperature dependence of a material is represented as the stress-strain relationship temperature dependence, a method to predict the fracture load at an arbitrary temperature from the already known fracture load at a reference temperature was proposed. This method was combined with the knowledge 'fracture stress for slip induced cleavage fracture is temperature independent.' Once the fracture load is predicted, fracture toughness J_c at the temperature under consideration can be evaluated by running elastic-plastic finite element analysis. Finally, the above-mentioned framework to predict the J_c temperature dependency of a material in the ductile-to-brittle temperature region was validated for 0.55% carbon steel JIS S55C. The proposed framework seems to have a possibility to solve the problem that the master curve is facing in the relatively higher temperature region, by requiring only tensile tests. (author)