Probabilistic prediction of the size effect on the fatigue strength for variable length specimens of selective laser melted 316L stainless steel

•Random defect size and location determines fatigue strength of the PBF-LB 316L stainless steel.•A void located in the subsurface volume initiates a fatigue crack.•Simulation of defect parameters and fatigue strength scatter using the Monte Carlo method.•Fatigue strength predicted using a probabilistic approach of the Kitagawa-Takahashi diagram.•Good prediction of the implemented Crossland normalized stress model. The paper presents an approach for modelling of the size effect in the high-cycle fatigue for an additively manufactured stainless steel. The analyses verify the probability of a critical defect, significantly speeding up fatigue crack initiation. An assessment of the fracture surface failure mechanism shows the presence of a void due to lack of fusion. The selected defect parameters significantly decrease the fatigue strength with increasing specimen length. The implemented linear model of the normalized Crossland stress provides a good fit to the experimental data. The probabilistic approach to the scatter of the selected variables shows the correct prediction of fatigue properties.