Calculation of characteristic size and fatigue life of structural members with blunt notches

Abstract

In order to evaluate notch effects and size effects on fatigue performances, smooth specimens without stress gradient and a group of notched specimens particularly designed are investigated in this paper. From the perspective of probability, the statistical size effect of the latter is worth studying for bodies weakened by notches. A unified model of combination of the improved theory of critical distance (TCD), along with the concept of highly-stressed-volume (CHSV) is established to identify the initiation crack size, evaluate the fatigue strength, and determine the fatigue lifetime of notched members, and even similar large-scale components in high cycle fatigue regime. The predicted results are compared with the experimental data sets taken from literatures. Fortunately, we find that, the novel model not only inherits the generality of existing methods, such as TCD, but also provides necessary support for predictions of characteristic length and fatigue lifetime of components containing any blunt-notch geometries.