A probabilistic fatigue assessment diagram to get a guaranteed lifetime with a low probability of failure

In order to guarantee a fatigue lifetime with a conventional and low probability of failure, a probabilistic fatigue assessment diagram is proposed as a tool. The safe domain is limited by the fatigue failure assessment curve, which depends on material properties through Basquin's exponent, the endurance limit and low cycle fatigue domain. From the double-truncated distribution of the targeted maximum applied stress, it is possible to find the probability of failure and its associated safety factor. An example of an aeronautical component made of TA6V titanium alloy welded by laser and exhibiting an undercut at the weld toe is given.