(Georgia Institute of Technology, 2023-10-11)
Sherman, Ryan J.; Kessler, Hannah D.; Frank, Karl H.; Medlock, Ronnie; Georgia Institute of Technology. School of Civil and Environmental Engineering
Wire arc additive manufacturing (WAAM) is an additive manufacturing process capable of printing using metallic feedstocks, such as traditional welding wire consumables. Advances in WAAM allow large-scale components, measured on the scale of feet, to be fabricated. A lack of fundamental knowledge of the material and fatigue behaviors of WAAM currently prevents its widespread adoption into structural engineering. To address this need, the first objective of this work was to create material property datasets for WAAM ER70S-6 and ER80S-Ni1through tension and notched bar impact (Charpy V-notch) tests. The second objective was to determine the influence of the as-fabricated surface finish on the fatigue behavior of WAAM ER70S-6 steel components through uniaxial fatigue tests on specimens. No significant anisotropy (difference in properties with respect to the build direction and deposition direction of the part) was noted in the yield and tensile strengths of the WAAM ER70S-6and ER80S-Ni1 material. Low levels of anisotropy were observed in the elongation at fracture of the tensile specimens and the impact energies of the CVN specimens. The impact energies of all WAAM specimens tested at or above the AASHTO service temperatures exceeded the fracture critical Grade 50 steel requirement. Fatigue specimens with the machined surface finish exceeded the upper bound life of AASHTO fatigue detail category A.A 95 percent confidence limit regression with the slope set to 3.0 for all the as-built surface specimens exceeded AASHTO fatigue detail category D.