Fatigue test data applicability for additive manufacture: A method for quantifying the uncertainty of AM fatigue data

Abstract

Additive manufactured (AM) components are increasingly being applied to fatigue-limited applications and are often safety–critical, necessitating confidence in the predicted fatigue response. The fatigue failure mode is highly sensitive to variations in loading, materials and geometry; therefore, published AM fatigue data must be accompanied by robust supporting documentation for confident adoption. International standards provide robust guidance on these documentation requirements; however, there are currently no formal methods for quantifying the uncertainty within published AM fatigue test data. A set of documentation criteria are proposed based on the core requirements of recognised standards for fatigue and AM test reporting. These documentation criteria form the basis for applicability indices proposed to quantify the uncertainty of reported AM fatigue test data. The applicability indices offer a new way to evaluate the suitability of fatigue data for specific applications and are demonstrated for publicly available Powder Bed Fusion Ti-6Al-4 V fatigue data. This large number of datasets are examined in terms of the influence of process variables on the observed fatigue response. These observations provide a reference for AM fatigue designers to be aware of the influence of relevant variables on fatigue response, as well as for AM fatigue researchers to identify strategic opportunities for novel contributions.