FE-Simulation of the influence by material defects on the endurance of additive built metal parts

The interaction between the process parameters in powder bed based additive manufacturing complicates the fatigue life prediction of the manufactured parts by a magnitude. A slight shift in a single parameter during a print job can lead to a highly divergent process result. The consequences can be observed in manufacturing defects inside the printed structure like pores and bonding defects which lead to locally inhomogeneous material properties. In this paper a method for predicting the fatigue life of additively manufactured structures based on the classical Stress-Life model is being developed. In a first step an experimental S-N curve for fatigue specimens is calculated by analyzing experimental data from literature. A Finite Element simulation of fatigue specimens with different internal defects is conducted and the life expectancy is determined. The specimens are built and inspected by means of destructive testing. The simulation is being validated and modified according to these results.