抄録
A critical examination was made on the applicability of linear fracture mechanics to creep and fatigue crack propagation at elevated temperatures. It was concluded that the stress intensity factor can be used in the analysis of crack propagation under creep condition so far as the applied load is tensile and the fracture is a plane strain intergranular type. In the case where bending load exists in addition to tensile load, the effect of redistribution of bending stress due to creep complicates the situation and the effective stress intensity becomes significantly lower than the elastic one. Consequently, a precaution has to be taken to select a proper specimen geometry in which no bending stress appears, when one tries to obtain the crack rate-stress intensity relation as fundamental data for crack analysis under creep condition.
