This research aims to experimentally investigate the ductile fracture characteristics and the level of anisotropy of four plates, 400 mm × 150 mm × 3.72 mm, made by Wire Arc Additive Manufacturing (WAAM) technology with 1 mm thick layers. Relatively small roughness is measured, expressed in maximum peak-to-valley height, measured by scanning, of 98 μm. Calibrated parameters for an advanced computational material model are derived for a finite element mesh size of 0.5 mm. The experimental campaign is based on eight types of short coupon specimens, analysed to explore fracture behaviour exposed to various stress conditions. Sixty-five coupon specimens, 51 milled and 14 tested in as printed conditions, cut out in three directions relative to the printing direction, are examined. The assumption of isotropic mechanical characteristics is confirmed. The mesoscale critical equivalent plastic strain (MCEPS) methodology is used to predict experimental results numerically. Three stages are considered: elastic, plastic, and couple plastic-damaged stages. The accuracy of the calibrated parameters is validated by comparing the engineering stress-strain relationships obtained from experimental tests and finite element (FE) analysis, reaching very good agreement. A list of all material parameters for ductile fracture modelling at various triaxiality levels and Lode parameters is provided for a mesh size of 0.5 mm.

In recent years, wire arc additive manufacturing (WAAM) has increasingly attracted attention in the construction sector because of its ability to optimize the production of large metallic structural parts, and for use in connections suitable for easy execution and potential reuse. The technology has become mature leading to shorter fabrication times and less expensive total costs due to lower raw material costs. Therefore, it is timely to conduct the material tests to evaluate the plastic flow and fracture of the WAAM steel plate to gain material characterization for an efficient design of connections. In this paper, the coupon specimens are cut from the WAAM plates in different directions in relation to the printing orientation to investigate possible material anisotropy. Results of uniaxial coupon specimens, the stress-strain curve, are analyzed in three stages: the elastic stage, the plastic stage and the coupled plastic-damage stage. The FE simulation is performed to calibrate the true stress and strain curves in different stages.