Material testing and analysis of WAAM stainless steel

Wire and arc additive manufacturing (WAAM) is a method of 3D printing that enables large structural elements to be built, with reasonable printing times and costs, making it well suited to applications in the construction industry. There is currently, however, limited information relating to the structural performance of WAAM material. Uncertainties include the basic mechanical properties, the degree of anisotropy and the influence of the as-built geometry. Towards addressing this knowledge gap, a comprehensive series of tensile tests on coupons cut from WAAM stainless steel sheets was conducted and the results are presented and analysed herein. As-built and machined coupons were tested to investigate the influence of the as-built geometrical irregularity on the stress-strain characteristics, while material anisotropy was explored by testing coupons produced at 0°, 45° and 90° to the printing layer orientation. Advanced non-contact measurement techniques were employed to determine the geometric properties and deformation fields of the test specimens, while sophisticated analysis methods were used for post processing the resulting test data. The underlying material stress-strain response, as determined from the tensile tests on the machined coupons, revealed a significant degree of anisotropy while the effective mechanical properties of the as-built material were shown to be strongly dependent on the level of geometric variability arising from the printing process. © 2021 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.