Digital design and manufacturing of a railway bogie demonstrator via multi-material wire arc directed energy deposition

Abstract

<p>The sequential digital design and manufacturing of components play a crucial role in realizing the industrial potential of directed energy deposition (DED), particularly when employing an electric arc as the energy source to melt a filler wire (DED-ARC). This study explores the application of DED-ARC for manufacturing large-scale, load-bearing structures, using a railway bogie as a case study. Originally a cast Bettendorf-type design, the bogie was redesigned using a multi-material approach. High-strength low-alloy (HSLA) steel was utilized in high-stress areas, while low-carbon steel was used elsewhere to reduce mass, enhance manufacturability, and improve repairability. The workflow included computer-aided design (CAD), topological optimization, finite element analysis (FEA), material selection, and iterative CAD modifications to address process constraints. The redesigned bogie underwent pre-manufacturing, fabrication, and a final scan of the as-built part. Representative multi-material wall samples were characterized, revealing typical microstructures and elastic limits of 468 MPa and 737 MPa for ER70S-6 and ER100S-G, respectively. These tensile properties were incorporated into FEA verification simulations, demonstrating a higher safety factor compared to the original design. A CAD-to-part analysis, including scan comparisons, highlighted manufacturing-induced deformation, material-dependent over-thickness, and localized geometric variations. This study offers a comprehensive overview of the DED-ARC process, from design through characterization, and demonstrates its capability to produce high-quality industrial components. The findings underscore the manufacturability and potential of DED-ARC for fabricating robust, multi-material structures for demanding applications.</p>