Fatigue life estimation of additively manufactured AISI 316L stainless steel

Additive manufacturing (AM) is becoming increasingly important in engineering applications due to its technological advantages such as: weight reduction, geometric complexity for functionalised products and near net-shape production. Despite the promising potential, the path towards a complete maturity of AM technology is still challenged by internal defects, which appear to be typical of the process. In particular, metal AM technologies are prone to internal defects, which can have a detrimental effect under fatigue loading. In such a context, the present paper deals with the fatigue life estimation of AISI 316L stainless steel subjected to cyclic loading. More precisely, the fatigue assessment is performed by means of an analytical methodology consisting of the joint application of: (i) a multiaxial stress-based fatigue criterion, named Carpinteri et al. criterion, which exploits the concept of the critical plane, and (ii) a stress averaging method, named Critical Direction Method, in order to determine the orientation of the critical plane. Satisfactory results are here obtained in terms of fatigue life for the examined specimens, regardless of both the specimen geometry (both plain and notched specimens are analysed) and the degree of multiaxiality and non-proportionality.