An improved, automated finite element analysis for fatigue life predictions of notched components

Among the causes for the breaking down of mechanical components, fatigue damage under cyclic stresses is by far the most common. Since this kind of damage is located in areas subject to the maximum cyclic stress amplitude, geometrical notches appear to be the most important site for fatigue failure. Understanding of the stress concentrators (notches) is an important element in the prevention of component failure, and is commonly assessed by a finite element analysis (FEA). In this research, it is intended to develop a methodology to automate the strain-based fatigue analysis in the FEA where the stress gradient and local plasticity effects are taken into account. The stress gradient effect is included by an empirical model to correlate the relative stress gradient (RSG) due to a stress raiser Kf, and the local notch plasticity with the fatigue notch factor is approximated by the modified Neuber rule. The FEA modelling guidelines to extract the RSG value are then proposed for improved accuracy.