Investigation of crack propagation rate under extremely low cycle fatigue considering the effect of stress ratio

Abstract

Safety evaluation of structures that requires extremely high reliability, such as power generation facilities, is essential. It is necessary to clarification of fracture criteria under extremely low cycle fatigue due to earthquakes, etc. It has been observed that the crack propagation rate changes at different stress ratios under high cycle fatigue, and a similar trend is expected to be observed under extremely low cycle fatigue. In this study, the purpose of paper is to propose the fracture criterion for crack propagation under extremely low cycle fatigue considering the effect of stress ratio for CT specimens with a thickness of 2 inches. As a fundamental study, crack propagation rate for different stress ratios was evaluated. In addition, the relationship between the crack propagation rate, which is closely related to the stress ratio, and the fracture criterion for crack propagation proposed in the previous study will be investigated.