Lattice me so-elements for a new class of green steel structures
LATTICE
Abstract
The growth of digitalization has recently prevailed in most of the production sectors, with the exception of the construction industry, in which the use of automation and additive manufacturing (AM) has been restricted to few pioneering applications. Among others, the most promising applications of AM in steel constructions are made with Wire-and-Arc Additive Manufacturing (WAAM), such as the world’s first steel AM footbridge in Amsterdam. WAAM offers a viable opportunity to build a new generation of efficient steel structures from both automated production and reduced material use, thanks to the freedom in printing highly efficient geometries. Within this framework, it is known that lattice structures are characterized by high efficiency (in terms of high stiffness and minimized material use), however their application at the scale of the single element (meso-scale), such as beams and columns, is still hampered by the issue of the connection at nodes (in terms of geometry complexity, assembly and production cost). Examples of current uses are caulked columns, limited to few high-rate applications. The ambition of the LATTICE project is to propose a new class of efficient structural elements by exploiting the efficiency of lattice structures at the meso scale with WAAM production technology. Indeed, WAAM allows to reduce the scale of truss/lattice systems to the single element by fabricating it as a whole, thus overcoming the issue of the physical node to connect straight parts. To achieve this main objective, the project aims at addressing the following goals: (a) full knowledge on WAAM manufacturing process for lattice meso-elements; (b) assessment of the mechanical properties of their basic components (straight bars and their intersections); (c) development of a computational design procedure for efficient lattice meso-elements accounting for the specific manufacturing, mechanical and structural constraints; (d) development of structural design guidelines for WAAM-produced lattice meso-elements. This requires an interdisciplinary effort in the fields of Structural Design, Manufacturing & Technology and Computational Mechanics, which are the three main research areas involved in the project. LATTICE is articulated in 3 main phases: BASIC, DESIGN, and MESO. Each phase consists of work packages (WP) aimed at designing, testing and validating a physical prototype of lattice meso-column. The BASIC phase will focus on the fabrication and mechanical characterization of the basic components of WAAM lattice meso-elements. The DESIGN phase will focus on the definition of the computational design procedure, through the development of a structural optimization tool for form-finding of lattice structural columns. The MESO phase will focus on the design, testing and validation of a prototype of a lattice meso-column.
Team di ricerca UNIBO
Tomaso Trombetti (P.I.), Giada Gasparini, Vittoria Laghi, Michele Palermo
Partner di progetto
Università di Napoli "Federico II", Politecnico di Milano