A study of ultra-low cycle fatigue failure based on a fracture strain energy model

Ductile failure under ultra-low cycle fatigue (ULCF) loading is often the limit service state of a nuclear structure. In the paper, ULCF tests for a C-Mn-Si steel are carried out. It is observed that the fracture displacement decreases as the number of fatigue cycles increases. An energy-based model, which considers the effects of both stress triaxiality and cyclic loading on the critical fracture strain energy, is proposed. Coupled with the new...