Endurance diagram

For the design of components that do not contain any defects and that are subjected to both alternating and mean stresses, a Soderberg diagram is normally used in a 'safe life' approach. However, structures may contain defects or cracks where a Soderberg diagram will not be sufficient. In this paper the development of an endurance diagram is presented for components that may contain crack-like defects left in the structure during the fabrication process. This diagram is based on the threshold stress intensity factor in fatigue crack growth, ΔKth, and the critical stress intensity factor, Kc. © 1990.