The theory of critical distances and fatigue from notches in aluminium 6061

Fatigue failure of metal components containing notches, cracks and other defects has been an active research topic for many years because of its important practical and theoretical implications. Recently, Taylor and his colleagues have re-visited this topic and proposed the theory of critical distance (TCD), which summarizes the early work by Neuber, Peterson and others in a unifying theory and predicts fatigue fracture with the use of a critical distance, Lo. In this paper, an experimental and numerical study of the fatigue of notched and un-notched 6061 aluminium alloys is used to verify the TCD and some of the limitations of the TCD are discussed on this basis.