Experimentally-validated buckling behavior of wire-arc additively manufactured stainless steel bars

Wire-and-Arc Additive Manufacturing (WAAM) is a metal 3D printing technology suitable to realize large-scale elements of complex form. The deposition strategy of metal can be either layer-by-layer, used for shells and solid parts, or dot-by-dot, resulting in bars and lattice structures. This latter has in particular the potential to realize new resource-efficient lightweight structural elements with reduced material use. The mechanical properties of dot-by-dot WAAM-produced stainless steel bars have been previously investigated under tensile and bending loading. The present work reports the results from experimental tests on the same bars with different lengths under compression loading to predict the buckling behavior of WAAM-produced slender elements. The different response of the specimens is governed by both the geometrical irregularities proper of the printing process and the different slenderness ratios of the tested specimens. The results are then interpreted according to the Eurocode approach, adapting the buckling curves proposed by the European structural design codes to WAAM stainless steel material properties. Finally, a new method to calibrate the overall imperfection factor proper of WAAM slender elements is proposed.