The design, fabrication, and structural and embodied carbon analysis of the world’s first manufactured topologically optimised multi-metal I-beam

Abstract This research focuses on the design, fabrication, and structural and embodied carbon analysis of the world’s first topologically optimised multi-metal I-beam. Specifically, the beam under study is a European Parallel I-beam with a nominal height of 100 mm (commonly referred to as ‘IPE-100’), and the materials used are mild steel and tool steel. Topology Optimisation (TO) is performed using Altair’s OptiStruct software package, applying the Solid Isotropic Material with Penalty (SIMP) method. The multi-metal beam is fabricated using 3D printing, specifically Laser Metal Deposition (LMD), with a dual built-in metal wire feeder attached to a robotic arm. The beam is analysed both environmentally and structurally — the former focusing on an embodied carbon assessment of material extraction and component manufacturing, and the latter on four-point structural load testing. The fabrication method and analysis results are compared with those of the standard IPE-100 beam currently used in construction. Environmentally, the Multi-Material Topologically Optimised (MMTO) beam’s reduced mass results in lower carbon emissions compared with the standard IPE-100; however, due to the high emissions associated with its fabrication process, its overall carbon footprint is higher. Structurally, the MMTO beam can withstand a higher machine load than the standard IPE-100 before undergoing plastic deformation. This research is the result of an international, multidisciplinary collaboration between academia and industry across the United Kingdom, Germany, and Spain.