Fatigue strength assessment of additively manufactured component considering local quality

Abstract

Direct energy deposition with wire and arc system (DED-Arc) is a form of additive manufacturing (AM), which is particularly advantageous for producing large-scale components. Surface waviness and local imperfections are typical in as-built DED-Arc components. In this study, literature data regarding fatigue performance of additive manufactured materials is gathered, and experimental tests for DED-Arc specimens are conducted to characterize typical features and relation between local quality and fatigue performance. Finite element modelling is used to evaluate local stresses, followed by obtaining effective stresses via theory of critical distances (TCD) approach. The findings are compared to literature data to evaluate fatigue strength assessment methods. The results indicated that quality-based modelling enables fatigue strength assessment with a reduced number of SN curves in comparison to the nominal stress method.