Diamond-shaped lattice steel structural elements realized with Wire-Arc Additive Manufacturing: Fabrication, testing and strength calibration

Lattice steel elements produced by Wire-Arc Additive Manufacturing (WAAM) are emerging as promising candidates for lightweight, architected structural members, yet their structural-scale behaviour remains largely unexplored. This paper investigates the structural response of WAAM-produced diamond-shaped lattice steel elements (D-Poles) under axial compression, providing the first comprehensive experimental dataset for this new class of components. D-Poles are formed by repetition of diamond-shaped units (D-Chips) along the height and around a polygonal cross-section, resulting in continuous lattice members without discrete mechanical connections. A fabrication campaign was carried out using a robotic WAAM setup with Cold Metal Transfer, producing three-, four- and six-faced D-Poles in three different heights (0.30 m, 0.60 m and 0.90 m). The specimens were characterized by industrial computed tomography to quantify porosity and thickness distribution, followed by monotonic compression tests on short and tall D-Poles. The global response is found to be governed by flexural behaviour of the D-Chips rather than by global buckling. An analytical model is adopted to interpret yielding and ultimate capacities and to develop a Eurocode-consistent calibration of characteristic and design strength values.